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This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your Class 12 knowledge and support exam preparation. Choose a topic below to get started.
| 401. |
Two hydrogen-like atoms A and B are of different masses and each atom contains equal number of protons and neutrons. The difference in the energies between the first Balmer lines emitted by A and B is 5.667 eV, when the atoms A and B, moving with the same velocity, strike a heavy target and rebound back with the same velocity. In the process, atom B imparts twice the momentum to the target than that A imparts. The series emitted is |
| Answer» <html><body><p>Lyman<br/>Balmer <br/>Pfund<br/>Paschen</p>Answer :<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a></body></html> | |
| 402. |
A wheel with N spokes is rotated in a plane - perpendicular to the magnetic field B such emf e is induced between axie and rim of the wheel . In the same wheel number of spokes is made 3 N and the wheel is rotated in the same manner in the same field then new emf is ________ . |
| Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :e Changing number of <a href="https://interviewquestions.tuteehub.com/tag/spokes-1222610" style="font-weight:bold;" target="_blank" title="Click to know more about SPOKES">SPOKES</a> does not change the <a href="https://interviewquestions.tuteehub.com/tag/area-13372" style="font-weight:bold;" target="_blank" title="Click to know more about AREA">AREA</a> <a href="https://interviewquestions.tuteehub.com/tag/swept-7331234" style="font-weight:bold;" target="_blank" title="Click to know more about SWEPT">SWEPT</a> per <a href="https://interviewquestions.tuteehub.com/tag/second-1197322" style="font-weight:bold;" target="_blank" title="Click to know more about SECOND">SECOND</a>.</body></html> | |
| 403. |
In an experiment for determination of refractive index of glass of a prism by i -delta ,plot, it was found that a ray incident at angle 35^(@) , suffers a deviation of 40^(@) and that it emerges an angle 79^(@) . In that case which of the following is closest to the maximum possible value of the refractive index? |
| Answer» <html><body><p>1.5<br/>1.6<br/>1.7<br/>1.8</p>Solution :`delta = I + e - A , `<a href="https://interviewquestions.tuteehub.com/tag/40-314386" style="font-weight:bold;" target="_blank" title="Click to know more about 40">40</a> = 30 + <a href="https://interviewquestions.tuteehub.com/tag/79-335953" style="font-weight:bold;" target="_blank" title="Click to know more about 79">79</a> - A<br/>4 = 114 - A , A = 114 - 40 = 74 = `r_(1)+r_(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>)`<br/>From this we get<br/>` mu=1.5`, `delta_(min)lt40^(@)`<br/>sin (((70+40)/2)/sin <a href="https://interviewquestions.tuteehub.com/tag/37-309797" style="font-weight:bold;" target="_blank" title="Click to know more about 37">37</a>), `:.mu_(max)=1.44`<br/><img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/NAR_NEET_PHY_XII_P3_C09_E06_025_S01.png" width="80%"/></body></html> | |
| 404. |
Net magnetic flux passing through any closed surface in a magnetic field is always ...... |
| Answer» <html><body><p>zero<br/>infinity<br/>definite<br/>indefinite</p>Solution :According to Gauss.s theorem, <br/> `<a href="https://interviewquestions.tuteehub.com/tag/oint-7840256" style="font-weight:bold;" target="_blank" title="Click to know more about OINT">OINT</a> overset(to)(B).overset(to)(d) s =0` <br/> `therefore oint"<a href="https://interviewquestions.tuteehub.com/tag/net-5194" style="font-weight:bold;" target="_blank" title="Click to know more about NET">NET</a>" =0`</body></html> | |
| 405. |
Draw the graph showing the variation of current with voltage for a p-n junction diode in forward bias as well as revese bias arrangements. |
| Answer» <html><body><p></p>Solution :The graph <a href="https://interviewquestions.tuteehub.com/tag/showing-642926" style="font-weight:bold;" target="_blank" title="Click to know more about SHOWING">SHOWING</a> the variation of current with voltage for a p-n junction (silicon) diode in (i) <a href="https://interviewquestions.tuteehub.com/tag/forward-464460" style="font-weight:bold;" target="_blank" title="Click to know more about FORWARD">FORWARD</a> <a href="https://interviewquestions.tuteehub.com/tag/bias-896549" style="font-weight:bold;" target="_blank" title="Click to know more about BIAS">BIAS</a>, and (ii) reverse bias has been drawn in . The graph in lst <a href="https://interviewquestions.tuteehub.com/tag/quadrant-1173739" style="font-weight:bold;" target="_blank" title="Click to know more about QUADRANT">QUADRANT</a> shows the forward bias characteristic curve and the graph in the third quadrant shows the reverse bias characteristic curve.<br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/U_LIK_SP_PHY_XII_C14_E09_006_S01.png" width="80%"/></body></html> | |
| 406. |
A car sounding its horn at 480 hz moves towards a high wall at a speed of 20 m/s . If the speed of sound is 340 ms^(-1) , the frequency of the reflected sound heard by the man sitting in the car will be nearest to : |
| Answer» <html><body><p>480 Hz<br/>540 Hz<br/>510 Hz<br/>570 Hz</p>Solution :The apparent frequency striking the wall is <br/> `v. = ((V)/(V - U_(s))) . V = (340xx480)/(340 - 20) = 510 ` Hz <br/> After reflection the wall <a href="https://interviewquestions.tuteehub.com/tag/acts-848461" style="font-weight:bold;" target="_blank" title="Click to know more about ACTS">ACTS</a> as source and man sitting in the car as observer who is moving towards the wall. <br/> `thereforev.. = ((V + U_(0))/(V) ) . v. = ((340 + 20)/(340) ) 510= 540 `Hz. <br/> thus <a href="https://interviewquestions.tuteehub.com/tag/correct-409949" style="font-weight:bold;" target="_blank" title="Click to know more about CORRECT">CORRECT</a> <a href="https://interviewquestions.tuteehub.com/tag/choice-915996" style="font-weight:bold;" target="_blank" title="Click to know more about CHOICE">CHOICE</a> is (<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a>).</body></html> | |
| 407. |
There is a vessel containing a liquid of refractive index 1.4. A point source of light is situated at a depth of 5 cm from the surface of the liquid. An opaque disc floats directly above the source of light. If anyone looks downwards from any point on the surface of the liquid and if the point source of light is not visible, what will be the minimum radius of the disc? |
| Answer» <html><body><p><br/></p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :5.1 <a href="https://interviewquestions.tuteehub.com/tag/cm-919986" style="font-weight:bold;" target="_blank" title="Click to know more about CM">CM</a></body></html> | |
| 408. |
How does radius of a nucleus vary with mass number ? Show that nuclear density is the same for all nuclei. |
| Answer» <html><body><p><<a href="https://interviewquestions.tuteehub.com/tag/p-588962" style="font-weight:bold;" target="_blank" title="Click to know more about P">P</a>> <br/> <br/></p>Solution :Variation of nuclear radius with mass number <br/> The dimensions of nucleus have been measured by several experiments involving the scattering of <a href="https://interviewquestions.tuteehub.com/tag/n-568463" style="font-weight:bold;" target="_blank" title="Click to know more about N">N</a>, p, `alpha`-particle etc. Every time it is found that the <a href="https://interviewquestions.tuteehub.com/tag/volume-728707" style="font-weight:bold;" target="_blank" title="Click to know more about VOLUME">VOLUME</a> of nucleus is directly proportional to the number of <a href="https://interviewquestions.tuteehub.com/tag/nucleons-1126012" style="font-weight:bold;" target="_blank" title="Click to know more about NUCLEONS">NUCLEONS</a> (A) in the nucleus.<br/> If R is the radius of the nucleus having mass number A, then<br/> `4/3 pi R^(3) prop A` <br/> or `R^(3) prop A` <br/> or `R prop A^(1//3)` <br/> or `R=A_(0)A^(1//3)` <br/> where `R_(0)=1.2xx10^(-15)m=1.2` fm. It shows that <a href="https://interviewquestions.tuteehub.com/tag/greater-476627" style="font-weight:bold;" target="_blank" title="Click to know more about GREATER">GREATER</a> the mass number, greater the nuclear radius. <br/> Density of nucleus `(rho)`. It is defined as the nuclear mass per unit volume. <br/> i.e. `rho=("Mass of nucleus")/("Volume of nucleus")` <br/> `=("Mass of one nucleon" xx "Number of nucleons")/(4/3 pi r^(3))` <br/> `=(1.66xx10^(-17)A)/(4/3 pi (R_(0)A^(1//3))^(3))` <br/> `=(3 xx 1.66 xx 10^(-27)A)/(4xx3.142xx(1.2xx10^(-15))^(3)xxA)` <br/> `=2.29xx10^(17)"kg m"^(-3)` <br/> Thus the nuclear density is of the order of `10^(17)` kg `m^(-3)` and independent of its mass number. Therefore, all nuclei have the same approximate density.</body></html> | |
| 409. |
The unit of electric dipole moment is: |
| Answer» <html><body><p></p>Solution :Electric <a href="https://interviewquestions.tuteehub.com/tag/dipole-440057" style="font-weight:bold;" target="_blank" title="Click to know more about DIPOLE">DIPOLE</a> moment is defined as the numerical product of charge and distance between the charges , and is directed from negative to <a href="https://interviewquestions.tuteehub.com/tag/positive-1159908" style="font-weight:bold;" target="_blank" title="Click to know more about POSITIVE">POSITIVE</a> charge.<br/><img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/OSW_SP_PHY_XII_C01_E01_008_S01.png" width="80%"/><br/>Unit : coulomb <a href="https://interviewquestions.tuteehub.com/tag/metre-1095305" style="font-weight:bold;" target="_blank" title="Click to know more about METRE">METRE</a> or <a href="https://interviewquestions.tuteehub.com/tag/cm-919986" style="font-weight:bold;" target="_blank" title="Click to know more about CM">CM</a>.</body></html> | |
| 410. |
A simple pendulum attached to the celling ofa stationary lift has time period T. The lift starts moving and the position vector of the lift is given as vecr(t)=15t^2hati+15t^2hatj, where r(t) is in meters and t is in seconds. If g=10 m//s^2, the new time period of oscillationis |
| Answer» <html><body><p>`T/sqrt(<a href="https://interviewquestions.tuteehub.com/tag/18-278913" style="font-weight:bold;" target="_blank" title="Click to know more about 18">18</a>)`<br/>`T/3`<br/>`T/sqrt5`<br/>`T/sqrt6`</p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :<a href="https://interviewquestions.tuteehub.com/tag/c-7168" style="font-weight:bold;" target="_blank" title="Click to know more about C">C</a></body></html> | |
| 411. |
A cell of emf E having an internal resistance r is connected to an external resistance R. The potential difference V across the resistance R varies with R as shown in figure by the curve: R |
| Answer» <html><body><p>A<br/><a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a><br/>C<br/>D</p>Answer :B</body></html> | |
| 412. |
Define current sensitivity of a moving coil galvanometer. |
| Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :<a href="https://interviewquestions.tuteehub.com/tag/deflection-17189" style="font-weight:bold;" target="_blank" title="Click to know more about DEFLECTION">DEFLECTION</a> <a href="https://interviewquestions.tuteehub.com/tag/per-590802" style="font-weight:bold;" target="_blank" title="Click to know more about PER">PER</a> <a href="https://interviewquestions.tuteehub.com/tag/unit-1438166" style="font-weight:bold;" target="_blank" title="Click to know more about UNIT">UNIT</a> current is called current Sensitivity.</body></html> | |
| 413. |
An object is placed in front of a concave mirror of focal length f as shown if figure. Choose the correct shape of the image : |
| Answer» <html><body><p><img src="https://doubtnut-static.s.llnwi.net/static/physics_images/AKS_TRG_AO_PHY_XII_V02_C_C02_E01_028_O01.png" width="30%"/> <br/><img src="https://doubtnut-static.s.llnwi.net/static/physics_images/AKS_TRG_AO_PHY_XII_V02_C_C02_E01_028_O02.png" width="30%"/> <br/><img src="https://doubtnut-static.s.llnwi.net/static/physics_images/AKS_TRG_AO_PHY_XII_V02_C_C02_E01_028_O03.png" width="30%"/> <br/><img src="https://doubtnut-static.s.llnwi.net/static/physics_images/AKS_TRG_AO_PHY_XII_V02_C_C02_E01_028_O04.png" width="30%"/> </p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a></body></html> | |
| 414. |
Statethe limitation of Bohr'stheory. |
| Answer» <html><body><p></p>Solution :<a href="https://interviewquestions.tuteehub.com/tag/although-7380138" style="font-weight:bold;" target="_blank" title="Click to know more about ALTHOUGH">ALTHOUGH</a> Bohr.s theory successfully explained the hydrogen spectrum in terms of only one quantum number , it was soon realised that this theory was not complete in itself and suffered from following main drawbacks: <br/>(i) Bohr.s theory cannot explain the spectrum of atoms having more than one electron. <br/>(ii) Even in hydrogen spectrum most spectral lines have their fine structure 1.c, each spectral line is a group of two or more lines situated close to one another. Bohr.s theory fails to explain the fine structure of the spectral lines. <br/>(iii) It can predict the frequencies (or wavelengths) of various spectral lines of hydrogen but is silent about the relative <a href="https://interviewquestions.tuteehub.com/tag/intensities-16135" style="font-weight:bold;" target="_blank" title="Click to know more about INTENSITIES">INTENSITIES</a> of the spectral lines. <br/>(iv) There is no <a href="https://interviewquestions.tuteehub.com/tag/logical-543774" style="font-weight:bold;" target="_blank" title="Click to know more about LOGICAL">LOGICAL</a> explanation of <a href="https://interviewquestions.tuteehub.com/tag/considering-7660792" style="font-weight:bold;" target="_blank" title="Click to know more about CONSIDERING">CONSIDERING</a> the shape of the electron orbits as <a href="https://interviewquestions.tuteehub.com/tag/circular-916697" style="font-weight:bold;" target="_blank" title="Click to know more about CIRCULAR">CIRCULAR</a>. Elliptical orbits are also possible.<br/> (v) While making calculations according to Bohr.s theory, we apply quantum condition at some places but adhere to classical laws of mechanics at other places. There is no justification for it.</body></html> | |
| 415. |
What are different types of wave fronts. |
| Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :<a href="https://interviewquestions.tuteehub.com/tag/spherical-650244" style="font-weight:bold;" target="_blank" title="Click to know more about SPHERICAL">SPHERICAL</a> <a href="https://interviewquestions.tuteehub.com/tag/wavefront-733858" style="font-weight:bold;" target="_blank" title="Click to know more about WAVEFRONT">WAVEFRONT</a>,<a href="https://interviewquestions.tuteehub.com/tag/cylindrical-429099" style="font-weight:bold;" target="_blank" title="Click to know more about CYLINDRICAL">CYLINDRICAL</a> wavefront <a href="https://interviewquestions.tuteehub.com/tag/plane-1155510" style="font-weight:bold;" target="_blank" title="Click to know more about PLANE">PLANE</a> wavefront.</body></html> | |
| 416. |
Name any two applications where eddy currents are used to advantage. |
| Answer» <html><body><p><br/></p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :<a href="https://interviewquestions.tuteehub.com/tag/electric-967871" style="font-weight:bold;" target="_blank" title="Click to know more about ELECTRIC">ELECTRIC</a> <a href="https://interviewquestions.tuteehub.com/tag/brakes-14257" style="font-weight:bold;" target="_blank" title="Click to know more about BRAKES">BRAKES</a>, <a href="https://interviewquestions.tuteehub.com/tag/speedometer-1221996" style="font-weight:bold;" target="_blank" title="Click to know more about SPEEDOMETER">SPEEDOMETER</a>.</body></html> | |
| 417. |
Standing waves can be produced to |
| Answer» <html><body><p>on a string clamped at both ends<br/>on a string clamped at one end and free at the other<br/> when incident wave gets reflected from a wall <br/>when two <a href="https://interviewquestions.tuteehub.com/tag/identical-496701" style="font-weight:bold;" target="_blank" title="Click to know more about IDENTICAL">IDENTICAL</a> waves with a phase <a href="https://interviewquestions.tuteehub.com/tag/difference-951394" style="font-weight:bold;" target="_blank" title="Click to know more about DIFFERENCE">DIFFERENCE</a> of `pi`are moving in the same direction </p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :A::B::C</body></html> | |
| 418. |
Consider an arbitrary electrostatic field configuration. A small test charge is placed at a null point (i.e., where E=0) of the configuration. Show that the equilibrium of the test charge is necessarily unstable. |
| Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :<a href="https://interviewquestions.tuteehub.com/tag/let-11597" style="font-weight:bold;" target="_blank" title="Click to know more about LET">LET</a> us consider that initially the test charge is in the <a href="https://interviewquestions.tuteehub.com/tag/stable-1223548" style="font-weight:bold;" target="_blank" title="Click to know more about STABLE">STABLE</a> <a href="https://interviewquestions.tuteehub.com/tag/equilibrium-974342" style="font-weight:bold;" target="_blank" title="Click to know more about EQUILIBRIUM">EQUILIBRIUM</a>. When the test charge is displaced from the null point (where, E = 0) in any direction, it must experience a restoring force towards the null point. <br/> This <a href="https://interviewquestions.tuteehub.com/tag/means-1091780" style="font-weight:bold;" target="_blank" title="Click to know more about MEANS">MEANS</a> that there is a net inward flux through a closed surface around the null point. According to the Gauss's theorem, the net electric flux through a surface net enclosing any charge must be zero. Hence, the equilibrium is not stable.</body></html> | |
| 419. |
Assertion : Transformers are used only in alternating current source not in direct current. Reason : Only a.c. can be stepped up or down by means of transformers. |
| Answer» <html><body><p>If both <a href="https://interviewquestions.tuteehub.com/tag/assertion-384238" style="font-weight:bold;" target="_blank" title="Click to know more about ASSERTION">ASSERTION</a> and reason are true and reason is the correct explanation of assertion<br/>If both assertion and reason are true but reason is not the correct explanation of assertion<br/>If assertion is true but reason is false<br/>If both assertion and reasonare false.</p>Solution :Trnasformers which convert low voltages into higher ones are called step-up transformers <a href="https://interviewquestions.tuteehub.com/tag/white-742716" style="font-weight:bold;" target="_blank" title="Click to know more about WHITE">WHITE</a> those which convert <a href="https://interviewquestions.tuteehub.com/tag/high-479925" style="font-weight:bold;" target="_blank" title="Click to know more about HIGH">HIGH</a> voltages into lower ones are called step-down transformers. This is <a href="https://interviewquestions.tuteehub.com/tag/possible-592355" style="font-weight:bold;" target="_blank" title="Click to know more about POSSIBLE">POSSIBLE</a> only for a.c. source and not for d.c. source.</body></html> | |
| 420. |
Draw a neat labelled diagram of diffraction image of an object. |
| Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :<img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/SPH_ABT_PHY_QB_XII_C10_E02_006_S01.png" width="80%"/></body></html> | |
| 421. |
Rank the following in the increasing oprder of rate of reaction with HBr |
| Answer» <html><body><p>`RgtPgtQ`<br/>`RgtQgtP`<br/>`PgtRgts`<br/>`PgtSgtR`</p>Solution :<img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/CP_JM_MT_09_E01_059_S01.png" width="80%"/> <br/> `+M(-NH)<a href="https://interviewquestions.tuteehub.com/tag/gt-1013864" style="font-weight:bold;" target="_blank" title="Click to know more about GT">GT</a> + M(O)gt + H(-CH_(<a href="https://interviewquestions.tuteehub.com/tag/3-301577" style="font-weight:bold;" target="_blank" title="Click to know more about 3">3</a>))` <br/> Rate of E.A.R propto <a href="https://interviewquestions.tuteehub.com/tag/stability-651358" style="font-weight:bold;" target="_blank" title="Click to know more about STABILITY">STABILITY</a> of <a href="https://interviewquestions.tuteehub.com/tag/carbocation-909158" style="font-weight:bold;" target="_blank" title="Click to know more about CARBOCATION">CARBOCATION</a> <br/> `propto(+M//H//+1)/(-M//-H//-1)` <br/> `(R )gt(P)gt(Q)`</body></html> | |
| 422. |
…….. does not change with time for D.C. current and D.C. voltage. |
| Answer» <html><body><p>only <a href="https://interviewquestions.tuteehub.com/tag/current-940804" style="font-weight:bold;" target="_blank" title="Click to know more about CURRENT">CURRENT</a><br/> only <a href="https://interviewquestions.tuteehub.com/tag/voltage-1447811" style="font-weight:bold;" target="_blank" title="Click to know more about VOLTAGE">VOLTAGE</a><br/>only power<br/>current, voltage and power</p>Answer :D</body></html> | |
| 423. |
STATEMENT 1: Energy stored in the capacitor is less than the energy battery during the charging of capacitor.because STATEMENT-2: Some of the energy is converted into heat. |
| Answer» <html><body><p>Statement-1 is <a href="https://interviewquestions.tuteehub.com/tag/true-713260" style="font-weight:bold;" target="_blank" title="Click to know more about TRUE">TRUE</a> , Statement-2 is True , Statement-2 is a <a href="https://interviewquestions.tuteehub.com/tag/correct-409949" style="font-weight:bold;" target="_blank" title="Click to know more about CORRECT">CORRECT</a> <a href="https://interviewquestions.tuteehub.com/tag/explanation-455162" style="font-weight:bold;" target="_blank" title="Click to know more about EXPLANATION">EXPLANATION</a> for Statement-1.<br/>Statement-1 is True , Statement-2 is True , Statement-2 is NOT a correct explanation for Statement-1.<br/>Statement-1 is True , Statement-2 is <a href="https://interviewquestions.tuteehub.com/tag/false-459184" style="font-weight:bold;" target="_blank" title="Click to know more about FALSE">FALSE</a> <br/>Statement-1 is False , Statement-2 is True </p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :A</body></html> | |
| 424. |
A bar magnet has a magnetic moment of 200 A m^(2).The magnet is suspended in a magnetic field of 0.30 N A^(-1)m^(-1) The torque required to rotate the magnet from its equilibrium position through an angle of 30^(@), will be |
| Answer» <html><body><p>30 N m<br/>`30 sqrt3 N m`<br/>60 N m<br/>`60sqrt3 <a href="https://interviewquestions.tuteehub.com/tag/nm-579234" style="font-weight:bold;" target="_blank" title="Click to know more about NM">NM</a>`</p>Solution :Torque experienced by a magnet suspended in a <a href="https://interviewquestions.tuteehub.com/tag/uniform-1437485" style="font-weight:bold;" target="_blank" title="Click to know more about UNIFORM">UNIFORM</a> magnetic <a href="https://interviewquestions.tuteehub.com/tag/field-987291" style="font-weight:bold;" target="_blank" title="Click to know more about FIELD">FIELD</a> <a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a> is given by <br/> `|vectau| = MB sintheta` <br/> Here, `M = 200 Am^(2), B = 0.30 N A^(-1) m^(-1)` <br/> and `<a href="https://interviewquestions.tuteehub.com/tag/theta-1412757" style="font-weight:bold;" target="_blank" title="Click to know more about THETA">THETA</a> = 30^(@)` <br/> `therefore |vectau|200xx0.30xxsin30^(@) implies vectau= 30Nm`</body></html> | |
| 425. |
The magnitude of electric field oversetto E due to a point charge in space around it has a ____________symmetry. |
| Answer» <html><body><p><br/></p>Solution :The magnitude of electric field ` (E=(<a href="https://interviewquestions.tuteehub.com/tag/q-609558" style="font-weight:bold;" target="_blank" title="Click to know more about Q">Q</a>)/(4piin _0r^(2)))` is same at allpoint at a distance <a href="https://interviewquestions.tuteehub.com/tag/r-611811" style="font-weight:bold;" target="_blank" title="Click to know more about R">R</a> from thepoint <a href="https://interviewquestions.tuteehub.com/tag/charge-914384" style="font-weight:bold;" target="_blank" title="Click to know more about CHARGE">CHARGE</a> ,so the field is exhibiting spherical <a href="https://interviewquestions.tuteehub.com/tag/symmetry-657996" style="font-weight:bold;" target="_blank" title="Click to know more about SYMMETRY">SYMMETRY</a>.</body></html> | |
| 426. |
At 20^@C,a brass cube has edge length 25 cm. What is the increase in the surface area when it is heated from 20^@Cto 75^@C? |
| Answer» <html><body><p><br/></p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :`7.8 cm^2`</body></html> | |
| 427. |
Explain with diagram, how current flows due to electron and hole in pure semiconductor. |
| Answer» <html><body><p></p>Solution :The semiconductor has the unique properties which the hole also moves in addition to the <a href="https://interviewquestions.tuteehub.com/tag/electrons-969138" style="font-weight:bold;" target="_blank" title="Click to know more about ELECTRONS">ELECTRONS</a>. <br/> <img src="https://doubtnut-static.s.llnwi.net/static/physics_images/KPK_AIO_PHY_XII_P2_C14_E01_075_S01.png" width="80%"/> <br/> Suppose there is a hole at site 1 as shown in figure (b). <br/> An electron from the covalent bond at site 2 may jump to the vacant site (hole). <br/> Thus, after such a jump, the hole is at site 2 and the site 1 has now an electron. <br/> Hence, the hole and the electrons move in opposite direction. Here <a href="https://interviewquestions.tuteehub.com/tag/due-433472" style="font-weight:bold;" target="_blank" title="Click to know more about DUE">DUE</a> to heat the electron released from the covalent bond do not involved in this process. <br/> The free electron moves completely independently as conduction electron and gives rise to an electron current, `I_(e )` under an applied <a href="https://interviewquestions.tuteehub.com/tag/electric-967871" style="font-weight:bold;" target="_blank" title="Click to know more about ELECTRIC">ELECTRIC</a> field. <br/> Hole is in a covalent bond. It move from high electric potential to low electric potential under the influence of external electric field applied when a hole is formed in a crystal. It is a convenient way of displaying and motion of hole created hole current. In thus, we get two type of <a href="https://interviewquestions.tuteehub.com/tag/currents-941646" style="font-weight:bold;" target="_blank" title="Click to know more about CURRENTS">CURRENTS</a> in semiconductors. <br/>(1) Due to motion of free electron. <br/> (2) Due to motion of formation of hole and instantaneous jumping electron in other hole.<br/> Hence in semiconductor, the total current I is the sum of the electron current `(I_(e ))` and the hole current `(I_(h))`. <br/> `therefore I=I_(e )+I_(h)`</body></html> | |
| 428. |
In Fraunhoffer diffraction, the wavelength incident light perpendicular to slit made double. the distance from the slit to the screen made tripled and if the width of the slit made (3)/(2) times then width of central maximum will be..... |
| Answer» <html><body><p> <a href="https://interviewquestions.tuteehub.com/tag/three-708969" style="font-weight:bold;" target="_blank" title="Click to know more about THREE">THREE</a> times <br/>four times<br/>doubled<br/>half </p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :In diffraction <a href="https://interviewquestions.tuteehub.com/tag/width-11498" style="font-weight:bold;" target="_blank" title="Click to know more about WIDTH">WIDTH</a> of central maximum mear <a href="https://interviewquestions.tuteehub.com/tag/distance-116" style="font-weight:bold;" target="_blank" title="Click to know more about DISTANCE">DISTANCE</a> between two <a href="https://interviewquestions.tuteehub.com/tag/minimum-561095" style="font-weight:bold;" target="_blank" title="Click to know more about MINIMUM">MINIMUM</a> <br/>Width of central maximum `alpha=(2lambdaD)/(d)` <br/> `:.` The new width obtained from modifying I and d, <br/> `alpha.=((2lambda)(3D))/(((3)/(3)))` <br/> `:.(alpha.)/(alpha)=4` <br/> `:.` Four times</body></html> | |
| 429. |
A thin string is held at one end andoscillates vertically so that,y = (x =0, t) = 8 sin (4t) (cm) Neglect the gravitational force. The string'slinearDiass density is 0.2 kg/m and its tension is 1 N. The string passes through a bath filled with 1 kg water, Due to friction heat is transferted to the bath. The heat transfer efficiency is 50%. Calculate how much time passes before the temperature of the bath rises by one degree kelvin. |
| Answer» <html><body><p><<a href="https://interviewquestions.tuteehub.com/tag/p-588962" style="font-weight:bold;" target="_blank" title="Click to know more about P">P</a>></p>Solution :Comparing the given equation with equation of a travelling wave, `kg//m` The <a href="https://interviewquestions.tuteehub.com/tag/average-13416" style="font-weight:bold;" target="_blank" title="Click to know more about AVERAGE">AVERAGE</a> power over a period is, `P = <a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>/2 (rho S) omega^2 A^2v` <br/> Substituting the values, we have <br/> `P = 1/2 (0.2) (<a href="https://interviewquestions.tuteehub.com/tag/4-311707" style="font-weight:bold;" target="_blank" title="Click to know more about 4">4</a>)^2 (8 xx 10^(-2))^2 (2.236) = 2.29 xx 10^(-2)J//s`<br/> Now let it take t second to raise the temperature of 1 kg water by one degree <a href="https://interviewquestions.tuteehub.com/tag/kelvin-1063402" style="font-weight:bold;" target="_blank" title="Click to know more about KELVIN">KELVIN</a>. Then `Pt = ms Deltat` <br/> Here, s = specific heat of water `= 4.2 xx 10^3 J//kg -K`<br/> `:. t = (msDeltat)/(P xx 1/2) = ((1) (4.2 xx 10^3) (1))/(1.145 xx 10^(-2)) ~~ 4.2` day</body></html> | |
| 430. |
Radio waves are _____ waves of wavelength 10^-3m and higher. |
| Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :<a href="https://interviewquestions.tuteehub.com/tag/electromagnetic-968633" style="font-weight:bold;" target="_blank" title="Click to know more about ELECTROMAGNETIC">ELECTROMAGNETIC</a></body></html> | |
| 431. |
Explain the quantization of angular momentum to behave an electron as wave in a atom. |
| Answer» <html><body><p></p>Solution :To introduce the atomic <a href="https://interviewquestions.tuteehub.com/tag/model-942" style="font-weight:bold;" target="_blank" title="Click to know more about MODEL">MODEL</a> Bohr in his second hypothesis said that the angular momentum of the electron orbiting around the nucleus is quantised. <br/> Louis de Broglie <a href="https://interviewquestions.tuteehub.com/tag/explain-447165" style="font-weight:bold;" target="_blank" title="Click to know more about EXPLAIN">EXPLAIN</a> this in 1923. <br/> According to de Broglie.s hypothesis material particles have a wave nature. Davisson and Germer experimentally verified the wave nature. <br/> Bohr <a href="https://interviewquestions.tuteehub.com/tag/proposed-1170346" style="font-weight:bold;" target="_blank" title="Click to know more about PROPOSED">PROPOSED</a> that the electron in a circular orbit should be as matter wave. <br/> The waves travelling on a string, particle waves too can lead to standing waves under resonant condition. <br/> When a string is plucked, a vast number of waves (wavelengths) are excited only those waves survive which have nodes at the ends and form the standing waves in the string. It means that in a string, standing waves are formed when the total distance <a href="https://interviewquestions.tuteehub.com/tag/travelled-7256865" style="font-weight:bold;" target="_blank" title="Click to know more about TRAVELLED">TRAVELLED</a> by a wave down the string and back is one wavelength, two wavelengths or any integral number of wavelength. <br/> Waves with other wavelength interfere with themselves upon reflection and their amplitudes <a href="https://interviewquestions.tuteehub.com/tag/quickly-610723" style="font-weight:bold;" target="_blank" title="Click to know more about QUICKLY">QUICKLY</a> drop to zero. Under this position the electron cannot remain in such orbit. <br/>For an electron moving in `n^(th)` circular orbit of radius `r_(n)` the total distance is the circumference of the orbit. <br/> `:.` Circumference of orbit = n wavelength <br/>`:. 2pi r_(n)= n lambda...(1) "where" n=1,2,3,...` <br/> <img src="https://doubtnut-static.s.llnwi.net/static/physics_images/KPK_AIO_PHY_XII_P2_C12_E01_024_S01.png" width="80%"/> <br/> Figure shows the standing wave located at the circular orbit for the four wavelength. <br/> Here n = 4 <br/>The relation of de Broglie wavelength and momentum <br/> `lambda=(h)/(p)=(h)/(mv_(n))....2 [ :. p=mv_(n)]` <br/> From equation (1) and (2), <br/> `2pi r_(n)=n((h)/(mv_(n)))` <br mv_=""/> which is the second hypothesis of Bohr atomic model. Momentum is always multiple integer of `(h)/(2pi)`. Hence, de Broglie explained the 211 quantization of the angular momentum of the orbiting electrons. The quantised electron orbits and energy states are due to the wave nature of the electron and only resonant standing waves can persist.</body></html> | |
| 432. |
Two capacitors of capacity 6 muF and 3 muF are charge 100 V and 50 V separately and connected as shown in (Fig.4.201.) Now all the three switches S_(1),S_(2), and S_(3) are closed. Charge on the 6 muF capacitor in steady state will be. |
| Answer» <html><body><p> `400 <a href="https://interviewquestions.tuteehub.com/tag/muc-1104776" style="font-weight:bold;" target="_blank" title="Click to know more about MUC">MUC</a>`<br/> `700 muC`<br/> `800 muC`<br/> `250 muC`</p>Solution : (1) `((150-x))/3+((600-x))/<a href="https://interviewquestions.tuteehub.com/tag/6-327005" style="font-weight:bold;" target="_blank" title="Click to know more about 6">6</a>-200=0` <br/> `x=-100 muC` <br/> Hence, final charge on `6 muF` Capacitor is <br/> `q_(1)=700 muC` and charge on `3 muF` is `q_(2)=250 muC` <br/> `q_(1)=(600-x) q_(2)=(150-x)` <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/BMS_V03_C04_E01_155_S01.png" width="80%"/>. <a href="https://interviewquestions.tuteehub.com/tag/plates-1156478" style="font-weight:bold;" target="_blank" title="Click to know more about PLATES">PLATES</a> `2` and `3` and plates `1` and `4` <a href="https://interviewquestions.tuteehub.com/tag/form-996208" style="font-weight:bold;" target="_blank" title="Click to know more about FORM">FORM</a> isolated system. <br/> Hence `q_(1)=q_(2)=q_(3)=x=-100 muC`.</body></html> | |
| 433. |
Two capacitors of capacity 6 muF and 3 muF are charge 100 V and 50 V separately and connected as shown in Now all the three switches S_(1),S_(2), and S_(3) are closed. Charge on the 3 muF capacitor in steady state willl be. |
| Answer» <html><body><p> `400 muC`<br/> `700 muC`<br/> `800 muC`<br/> `<a href="https://interviewquestions.tuteehub.com/tag/250-297421" style="font-weight:bold;" target="_blank" title="Click to know more about 250">250</a> muC`</p>Solution : (<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>) `((150-x))/<a href="https://interviewquestions.tuteehub.com/tag/3-301577" style="font-weight:bold;" target="_blank" title="Click to know more about 3">3</a>+((600-x))/6-200=0` <br/> `x=-100 muC` <br/> Hence, final charge on `6 muF` Capacitor is <br/> `q_(1)=700 muC` and charge on `3 muF` is `q_(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>)=250 muC` <br/> `q_(1)=(600-x) q_(2)=(150-x)` <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/BMS_V03_C04_E01_156_S01.png" width="80%"/>. Plates `2` and `3` and plates `1` and `4` form isolated <a href="https://interviewquestions.tuteehub.com/tag/system-1237255" style="font-weight:bold;" target="_blank" title="Click to know more about SYSTEM">SYSTEM</a>. <br/> Hence `q_(1)=q_(2)=q_(3)=x=-100 muC`.</body></html> | |
| 434. |
Six wires of current I_1 = 1A, I_2 = 2 A, I_3 = 3A, I_4 = 1A, I_5 = 5A and I_6 = 4A cut the page perpendicularly at the points 1, 2,3,4,5 and 6. respectively as shown in the figure . Find the value of the integraloint vec B.d vec1 around the closed path. |
| Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :`mu_0 " <a href="https://interviewquestions.tuteehub.com/tag/weber-734178" style="font-weight:bold;" target="_blank" title="Click to know more about WEBER">WEBER</a>."m^(-<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>)`</body></html> | |
| 435. |
A food packet is dropped from a helicopter rising up with a velocity of 4m/s. The velocity of the packet after three seconds will be |
| Answer» <html><body><p>20.4`m/s`<br/>`25.4m/s`<br/>`28.4m/s` <br/>`30.4m/s`</p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a></body></html> | |
| 436. |
The electricalis present in |
| Answer» <html><body><p>AND<br/>OR <br/>NOR <br/>NAND</p>Solution :AND</body></html> | |
| 437. |
In copper voltameter 20mg of copper is deposited on thecathode of the voltameter by 0.15-wedgecurrent in 6minutes 42sec. Calculate (i) amount of electricity required to liberate one gram equivalent of any substance, (ii) charge carried by an electron. (Atomic mass of copper =64l Avogardo constant==6.02xx10^(23)"mol"^(-1) and copper is divalent.) |
| Answer» <html><body><p><br/></p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :`(i)96500C, (<a href="https://interviewquestions.tuteehub.com/tag/ii-1036832" style="font-weight:bold;" target="_blank" title="Click to know more about II">II</a>)1.6xx10^(-<a href="https://interviewquestions.tuteehub.com/tag/19-280618" style="font-weight:bold;" target="_blank" title="Click to know more about 19">19</a>)<a href="https://interviewquestions.tuteehub.com/tag/c-7168" style="font-weight:bold;" target="_blank" title="Click to know more about C">C</a>`</body></html> | |
| 438. |
A convex lens of focal length 2.5 cm is used as a magnifying glass. In normal adjustment its magnifying power is ____________. |
| Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :<a href="https://interviewquestions.tuteehub.com/tag/hint-486738" style="font-weight:bold;" target="_blank" title="Click to know more about HINT">HINT</a> : In normal adjustment `m=<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>+(D)/(f)=1+(25 cm)/(2.5 cm)=<a href="https://interviewquestions.tuteehub.com/tag/11-267621" style="font-weight:bold;" target="_blank" title="Click to know more about 11">11</a>`</body></html> | |
| 439. |
A fish rising vertically to the surface of water in a lake uniformly at the rate of 3ms^(-1) observes a bird diving vertically towards the water at a rate of 9ms^(-1) vertically above it. If the refractive index of water is 4/3 the actual velocity of the dive of the bird is (in ms^(-1)) |
| Answer» <html><body><p>6<br/>4.5<br/>1.5<br/>2</p>Answer :<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a></body></html> | |
| 440. |
A million electrons pass through a cross-section of a conductor in 10^(-3) sec. What is the current in ampere ? |
| Answer» <html><body><p>`1.6xx10^(-<a href="https://interviewquestions.tuteehub.com/tag/7-332378" style="font-weight:bold;" target="_blank" title="Click to know more about 7">7</a>)`<br/>`1.6xx10^(-<a href="https://interviewquestions.tuteehub.com/tag/10-261113" style="font-weight:bold;" target="_blank" title="Click to know more about 10">10</a>)`<br/>`1.6xx10^(-<a href="https://interviewquestions.tuteehub.com/tag/4-311707" style="font-weight:bold;" target="_blank" title="Click to know more about 4">4</a>)`<br/>`1.6xx10^(-11)`</p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a></body></html> | |
| 441. |
For what purpose is a refracting prism used along with a spectrometer? |
| Answer» <html><body><p></p>Solution :A refracting <a href="https://interviewquestions.tuteehub.com/tag/prism-1166613" style="font-weight:bold;" target="_blank" title="Click to know more about PRISM">PRISM</a> is <a href="https://interviewquestions.tuteehub.com/tag/used-2318798" style="font-weight:bold;" target="_blank" title="Click to know more about USED">USED</a> to <a href="https://interviewquestions.tuteehub.com/tag/measure-1091857" style="font-weight:bold;" target="_blank" title="Click to know more about MEASURE">MEASURE</a> the refractive indices of lights of different colours and <a href="https://interviewquestions.tuteehub.com/tag/hence-484344" style="font-weight:bold;" target="_blank" title="Click to know more about HENCE">HENCE</a> their wavelengths.</body></html> | |
| 442. |
Nuclear reactor in which luranium-235 is used as fuel, uses 2 kg of uranium-235 in 30 days. Then power output of the reactor will be (given : Energy released per fission =185 MeV): |
| Answer» <html><body><p>43.5 MW <br/>58.5 MW <br/>69.6 MW <br/>73.1 MW </p>Solution :<a href="https://interviewquestions.tuteehub.com/tag/number-582134" style="font-weight:bold;" target="_blank" title="Click to know more about NUMBER">NUMBER</a> of <a href="https://interviewquestions.tuteehub.com/tag/atoms-887421" style="font-weight:bold;" target="_blank" title="Click to know more about ATOMS">ATOMS</a> in <a href="https://interviewquestions.tuteehub.com/tag/2kg-300729" style="font-weight:bold;" target="_blank" title="Click to know more about 2KG">2KG</a> of <a href="https://interviewquestions.tuteehub.com/tag/uranium-1440633" style="font-weight:bold;" target="_blank" title="Click to know more about URANIUM">URANIUM</a> <br/> `=(6.02 xx 10^(23))/(<a href="https://interviewquestions.tuteehub.com/tag/235-1826120" style="font-weight:bold;" target="_blank" title="Click to know more about 235">235</a>) xx 2000=5.12 xx 10^(24)` <br/> Energy released `=5.12 xx 10^(24) xx 185MeV` <br/> Time taken =30 days <br/> Energy released per second <br/> `= (5.12 xx 10^(24) xx 185 xx 1.6 xx 10^(-13))/(30 xx 24 xx 60 x 60)=58.47MW`</body></html> | |
| 443. |
Two point charges q_1 and q_2 of magnitude +10^(-8) Cand -10^(-8) Crespectively are placed 0.1 m apart . Calculate the electric field at point B ,C and A(##U_LIK_SP_PHY_XII_C01_E10_021_Q01.png" width="80%"> |
| Answer» <html><body><p></p>Solution :<a href="https://interviewquestions.tuteehub.com/tag/given-473447" style="font-weight:bold;" target="_blank" title="Click to know more about GIVEN">GIVEN</a> charges ` q_1 and q_2 ` constitute an electric dipole of dipole moment ` p=q 2a =10 ^(-8)xx <a href="https://interviewquestions.tuteehub.com/tag/0-251616" style="font-weight:bold;" target="_blank" title="Click to know more about 0">0</a>.1 = 10 ^(-9)C -m ` <br/> (i)Point B lies on the axial line of dipole, where ` "" r= 0.05 + 0.05 =0.1 m , `hence<br/> ` E_B =(1)/( <a href="https://interviewquestions.tuteehub.com/tag/4-311707" style="font-weight:bold;" target="_blank" title="Click to know more about 4">4</a> pi in _0).(2pr)/( (r^(2) -a^(2)) ^(2)) `<br/> ` "" ( 9xx 10^(9) xx 2 xx 10^(-9) xx 0.1 )/([(0.1)^(2) -(0.05) ^(2) ]^(2)) =3.2 xx 10 ^(4)N//C `directed along NM. <br/>(<a href="https://interviewquestions.tuteehub.com/tag/ii-1036832" style="font-weight:bold;" target="_blank" title="Click to know more about II">II</a>) Point C lies on the equatorial line of dipole ,where ` sqrt ( a^(2) +r^(2)) = 0.1 m, ` hence <br/> ` <a href="https://interviewquestions.tuteehub.com/tag/therefore-706901" style="font-weight:bold;" target="_blank" title="Click to know more about THEREFORE">THEREFORE</a> E_C =(1)/( 4 pi in _0) . (p)/( (a^(2) +r^(2)) ^(3//2))=(9xx 10^(9) xx 10 ^(9)) /( (0.1)^(3))= 9xx 10 ^(3) N//C ` along MN. <br/> (iii) Point A also lies at equatorial line where r=0 <br/>`therefore ""E_A=(1)/( 4 pi in _0) .(p)/(a^(3)) =(9xx 10^(9) xx 10 ^(-9))/((0.05)^(3))=7.2 xx 10 ^(4) N//C ` along MN.</body></html> | |
| 444. |
Theradius of an electron orbit in a hydrogen atom is of the order of |
| Answer» <html><body><p>`<a href="https://interviewquestions.tuteehub.com/tag/10-261113" style="font-weight:bold;" target="_blank" title="Click to know more about 10">10</a>^(-<a href="https://interviewquestions.tuteehub.com/tag/8-336412" style="font-weight:bold;" target="_blank" title="Click to know more about 8">8</a>)` m<br/>`10^(-<a href="https://interviewquestions.tuteehub.com/tag/9-340408" style="font-weight:bold;" target="_blank" title="Click to know more about 9">9</a>)`m<br/>`10^(-11)`m<br/>`10^(-<a href="https://interviewquestions.tuteehub.com/tag/13-271882" style="font-weight:bold;" target="_blank" title="Click to know more about 13">13</a>)`m</p>Answer :C</body></html> | |
| 445. |
Use the mirror equation to deduce that : (a) an object placed between f and 2f of a concave mirror produces a real image beyond 2f. (b) a convex mirror always produces a virtual image independent of the locatioin of the object. (c ) the virtual image produced by a convex mirror is always diminished in size and is located between the focus and the pole. (d) an object placed between the pole and focus of a concave mirror procuces a virtual and enlarged image. |
| Answer» <html><body><p></p>Solution :(a) As per <a href="https://interviewquestions.tuteehub.com/tag/mirror-1098189" style="font-weight:bold;" target="_blank" title="Click to know more about MIRROR">MIRROR</a> formula: `1/v + 1/u = 1/f` <br/> `therefore 1/v = 1/f -1/u` and for concave mirror u and f both are <a href="https://interviewquestions.tuteehub.com/tag/negative-570381" style="font-weight:bold;" target="_blank" title="Click to know more about NEGATIVE">NEGATIVE</a> i.e. `f lt 0` and `<a href="https://interviewquestions.tuteehub.com/tag/mu-566056" style="font-weight:bold;" target="_blank" title="Click to know more about MU">MU</a> lt 0` <b> If `2f lt u lt f`, then `1/(2f) <a href="https://interviewquestions.tuteehub.com/tag/gt-1013864" style="font-weight:bold;" target="_blank" title="Click to know more about GT">GT</a> 1/u gt 1/f` or `-1/(2f) lt -1/u lt -1/f` <br/> or `1/(2f) lt 1/v lt 0` <br/> Thus, `v gt 2f`with a negative sign i.e., the image is real and lies beyond 2f. <br/> (b) For a concave mirror `1/v =1/f -1/u` but f si positive and u is negative i.e. <br/> `1/v = 1/f -1/(-u) =1/f + 1/u = +ve` <br/> Therefore, irrespective of the value of u, value of v is always +ve. It means that the image formed by convex mirror is always virtual independent of the location of the object. <br/> ( c) As for a convex mirror f is +ve and u is -ve, hence <br/> `1/v =1/f -1/(-u) = 1/f + 1/u` <br/> It means that `1/v gt 1/u` or `|v| lt |u|`. Thus, `m =h^(.)/h =|v|/|u| lt 1` i.e, the image is diminished one . <br/> Moreover, from above, it is clear that `1/v gt 1/f` or `|v| lt |f|` <br/> moreover from the above, it is clear that `1/v gt 1/f` or `|v| lt |f|` <br/>Hence, the image is located between the <a href="https://interviewquestions.tuteehub.com/tag/pole-1157556" style="font-weight:bold;" target="_blank" title="Click to know more about POLE">POLE</a> and principal focus of convex mirror. <br/> (d) As for a concave mirror f and u both are negative, hence <br/> `1/v =1/(-f) -1/(-u) =1/u -1/f` <br/> if `|v| lt |f|`, then `1/u gt 1/f` and hence, `1/v gt 0` i.e. is `+ve`. Moreover `1/v lt 1/u` or `v gt u`.It means that for an object placed between the pole and principal focus of a concave mirror the image formed is virtual and magnification`|m| |v|/|u| gt 1`</b></body></html> | |
| 446. |
A gamma ray photon of energy 1896 MeV annihilates to produce a proton-antiproton pair. If the rest mass of each of the particles involved be 1.007276 a.m.u approximately, find how much K.E these will carry? |
| Answer» <html><body><p></p>Solution :Working on the same lines as an electron-positron <a href="https://interviewquestions.tuteehub.com/tag/pair-1145723" style="font-weight:bold;" target="_blank" title="Click to know more about PAIR">PAIR</a> production, we notice that the <a href="https://interviewquestions.tuteehub.com/tag/reaction-22747" style="font-weight:bold;" target="_blank" title="Click to know more about REACTION">REACTION</a>.`gamma to`proton + antiproton, has the energy balance <br/> `E=m_(0"(proton)") C^2+K.E_"(proton)" + m_(0"(antiproton)") C^2+K.E_"(antiproton)"` <br/> But `m_0C^2` = energy equivalent of 1.007276 a.m.u. `<a href="https://interviewquestions.tuteehub.com/tag/approx-882876" style="font-weight:bold;" target="_blank" title="Click to know more about APPROX">APPROX</a>` 938 MeV . <br/> [`because` 1.007276 x 931 `approx` 938 MeV] <a href="https://interviewquestions.tuteehub.com/tag/thus-2307358" style="font-weight:bold;" target="_blank" title="Click to know more about THUS">THUS</a> K.E. of each particle =`1/2`[1896 MeV-2 x 938 MeV] =10 MeV</body></html> | |
| 447. |
Compare the amount of work done in blowing soap bubbles of radii 3cm and 4cm |
| Answer» <html><body><p>0.38611111111111<br/>0.26111111111111<br/>0.33958333333333<br/>0.34444444444444</p>Answer :A</body></html> | |
| 448. |
In the Young's double slit experiment apparatus shown in figure Deltax is P the path difference between S_(2)P and. S_(1)P. Now a glass slab is introduced in front of S_(2) , then match the following |
| Answer» <html><body><p><br/></p><a href="https://interviewquestions.tuteehub.com/tag/answer-15557" style="font-weight:bold;" target="_blank" title="Click to know more about ANSWER">ANSWER</a> :A</body></html> | |
| 449. |
A shell is fired from a cannon, it explodes in mid air, its total |
| Answer» <html><body><p><a href="https://interviewquestions.tuteehub.com/tag/momentum-1100588" style="font-weight:bold;" target="_blank" title="Click to know more about MOMENTUM">MOMENTUM</a> increases<br/>momentum decreases<br/>KE increases<br/>KE decreases</p>Answer :<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a></body></html> | |
| 450. |
Explain dielectric constant with expressions . |
| Answer» <html><body><p></p>Solution :When two point charges `q_(1)andq_(2)` are at a distance r from each other in air . The <a href="https://interviewquestions.tuteehub.com/tag/coulomb-426789" style="font-weight:bold;" target="_blank" title="Click to know more about COULOMB">COULOMB</a> force between them <br/>`F_(1) = (1)/(4piepsilon_(0))(q_(1)q_(2))/(Kr^(2))`<br/>Where `epsilon_(0)` is the permittivity of <a href="https://interviewquestions.tuteehub.com/tag/thefree-2304326" style="font-weight:bold;" target="_blank" title="Click to know more about THEFREE">THEFREE</a> space . Ifa medium of <a href="https://interviewquestions.tuteehub.com/tag/dielectric-951238" style="font-weight:bold;" target="_blank" title="Click to know more about DIELECTRIC">DIELECTRIC</a> constant K is <a href="https://interviewquestions.tuteehub.com/tag/filled-2641169" style="font-weight:bold;" target="_blank" title="Click to know more about FILLED">FILLED</a> in the space between them Coulomb force<br/>`F_(2)=(1)/(4piepsilon_(0))(q_(1)q_(2))/(r^(2))`<br/>`therefore(F_(1))/(F_(2))=K`<br/>Therefore the ratio of the forces between the charges when placed in air and when placed in the medium at the same distance is known as the dielectric constant of that medium. <br/>We know that<br/>`<a href="https://interviewquestions.tuteehub.com/tag/epsilon-973455" style="font-weight:bold;" target="_blank" title="Click to know more about EPSILON">EPSILON</a>=epsilon_(0)K`<br/>`K=(epsilon)/(epsilon_(0))`<br/> orDielectric constant `=("Permittivity of the medium")/("Permittivity of the free space")`</body></html> | |