Explore topic-wise InterviewSolutions in Class 12.

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.

45251.

How can you detect a polarized light?

Answer» <html><body><p></p>Solution :Take two tourmaline <a href="https://interviewquestions.tuteehub.com/tag/crystals-940110" style="font-weight:bold;" target="_blank" title="Click to know more about CRYSTALS">CRYSTALS</a> `T_(1)` and `T_(2)` cut with their <a href="https://interviewquestions.tuteehub.com/tag/faces-982657" style="font-weight:bold;" target="_blank" title="Click to know more about FACES">FACES</a> <a href="https://interviewquestions.tuteehub.com/tag/parallel-1146369" style="font-weight:bold;" target="_blank" title="Click to know more about PARALLEL">PARALLEL</a> to the axis of the crystal. A <a href="https://interviewquestions.tuteehub.com/tag/fine-989069" style="font-weight:bold;" target="_blank" title="Click to know more about FINE">FINE</a> beam of light from the source S is passed through `T_(1)` and light is observed by placing eye behind `T_(2)`. <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/MBD_EM_PHY_XII_C06_E02_034_S01.png" width="80%"/> <br/> When the axis of `T_(1)` and `T_(2)` are parallel, maximum light is observed [Fig. (i)] but when the axis of `T_(1)` and `T_(2)` are crossed (<a href="https://interviewquestions.tuteehub.com/tag/perpendicular-598789" style="font-weight:bold;" target="_blank" title="Click to know more about PERPENDICULAR">PERPENDICULAR</a>), then practically no light is observed. This phenomenon can only be explained if light waves are transverse. Light falling on `T_(1)` has transverse vibrations lying in all possible directions. `T_(1)` allows only vibrations which are parallel to the axis of `T_(1)` . If second crystal `T_(2)` is placed parallel to `T_(1)` as in first figure, then vibrations transmitted by `T_(1)` are also transmitted by `T_(2)`. If `T_(2)` is perpendicular to `T_(1)`, the vibrations from `T_(1)` are perpendicular to the axis of `T_(2)`. Hence `T_(2)` will not allow these vibrations to pass [Fig. (ii)]. <br/> Longitudinal vibrations can however pass through slits irrespective of their orientations. This is the reason as to why the sound waves cannot be polarised. <br/> Due to the change of the intensity of polarised light as a result of relative orientation of their crystallographic axis, it is concluded that the light waves must be transverse in nature.</body></html>
Discussion
45252.

Luminous intensites of two sources of light are compared using a

Answer» <html><body><p><a href="https://interviewquestions.tuteehub.com/tag/polarimeter-15995" style="font-weight:bold;" target="_blank" title="Click to know more about POLARIMETER">POLARIMETER</a> <br/><a href="https://interviewquestions.tuteehub.com/tag/photometer-1153528" style="font-weight:bold;" target="_blank" title="Click to know more about PHOTOMETER">PHOTOMETER</a> <br/><a href="https://interviewquestions.tuteehub.com/tag/spectrometer-1221778" style="font-weight:bold;" target="_blank" title="Click to know more about SPECTROMETER">SPECTROMETER</a> <br/>Photomultiplier</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>
Discussion
45253.

Derivesigma=("ne"^2 tau)/m, where the symbols have their usual meaning.

Answer» <html><body><p></p>Solution :Let .n. be the numberdensityof electrons , .L. be the lengthof the <a href="https://interviewquestions.tuteehub.com/tag/conductora-8288920" style="font-weight:bold;" target="_blank" title="Click to know more about CONDUCTORA">CONDUCTORA</a> and .A.be the areaof cross -sectionof the conductor . <br/>Let `v_d` be the drift <a href="https://interviewquestions.tuteehub.com/tag/velocityof-3259016" style="font-weight:bold;" target="_blank" title="Click to know more about VELOCITYOF">VELOCITYOF</a> the electrons and Dx be a small length . <br/>Electrons drift in a directionoppositeto the electric field. Number ofelectronsin .Dx.and area of cross -section .A.is equal to (ADx) n. <br/>Charge on the theseelectrons =(nADx)e. <br/> If Dt is the time taken for effectivedisplacementof electronsthen rate of flow charge = `nAe ((Deltax)/(Deltat))` .<br/> By <a href="https://interviewquestions.tuteehub.com/tag/definition-11288" style="font-weight:bold;" target="_blank" title="Click to know more about DEFINITION">DEFINITION</a>,electric current I=rate of flowof charge <br/> i.e.,`I=nAev_d`...(1) <br/>where , average velocityof electrons with whichit drifts againstthe directionof electric field is known as drift velocity`(v_d)`. <br/> Let .a. be the accelerationof electrons. Let .E.be the electricfieldintensity . Force on electrons, <br/> F=ma <br/> i.e., eE=ma <br/> But = `a=v_dt` where .t.is the relaxationtime . <br/> Relaxationtime representsthe average timetaken for two successivecollisionsof electronsand ionsin the lattice. <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/SPH_PHY_HND_BOK_PUC_QP_JUN_18_E01_028_S01.png" width="80%"/> <br/> Hence ,`eE=mv_dt` or `v_d=(eE)/(mtau)` ...(2) <br/>We alsoknow that electricpotentialdifferencebetween the ends of the conductorV=EL <br/> `v_d =(eV)/(mtauL)` substitutingthis is the expression (1) <br/>We write, `I=nAe ((eV)/(mtauL))` <br/> i.e., `I=((nAe^2)/(mtauL))V` <br/> `R=(mtau L)/(nAe^2)`is called the electricalresistanceof a conductor . and `K=((nAe^2)/(mtauL))` is called the electric conductance of a conductor . the expression `sigma =("<a href="https://interviewquestions.tuteehub.com/tag/ne-1112263" style="font-weight:bold;" target="_blank" title="Click to know more about NE">NE</a>"^2)/(mtau)` is called the electricalconductivityand `1/sigma=(mtau)/("ne"^2)` is called electricalresistivity .</body></html>
Discussion
45254.

In a head-on collision between an alpha-particle and a gold nucleus, the distance of closest approach is 39.5 fermi. Calculate the energy of alpha-particle. For gold Z=79.

Answer» <html><body><p> <br/> <br/></p>Solution :Given `r_(0)=39.5 "fm"=39.5xx10^(-15)m, =79, <a href="https://interviewquestions.tuteehub.com/tag/e-444102" style="font-weight:bold;" target="_blank" title="Click to know more about E">E</a>=?` <br/> As `E=(Ze(2e))/(4 pi epsilon_(0)<a href="https://interviewquestions.tuteehub.com/tag/r-611811" style="font-weight:bold;" target="_blank" title="Click to know more about R">R</a>)=(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a> Ze^(2))/(4 pi epsilon_(0)r)` <br/> `=(9xx10^(9)xx79xx2xx(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>))^(2))/(39.5xx10^(-15))` <br/> `=(9xx79xx2xx1.6xx1.6xx10^(-14))/(39.5)J` <br/> or `E=(18xx79xx1.6xx1.6xx10^(-14))/(39.5xx1.6xx10^(-13))` <br/> `=5.76` M eV.</body></html>
Discussion
45255.

If an earth satellite is put in orbit at a height where resistance due to the atomosphere cannot be neglected, how will the motion of a satellite be affected ?

Answer» <html><body><p></p>Solution :For a satellite, moving in a circular <a href="https://interviewquestions.tuteehub.com/tag/orbit-1138163" style="font-weight:bold;" target="_blank" title="Click to know more about ORBIT">ORBIT</a> of <a href="https://interviewquestions.tuteehub.com/tag/radius-1176229" style="font-weight:bold;" target="_blank" title="Click to know more about RADIUS">RADIUS</a> r orbital velocity `V_0=sqrt((GM)/r)<a href="https://interviewquestions.tuteehub.com/tag/therefore-706901" style="font-weight:bold;" target="_blank" title="Click to know more about THEREFORE">THEREFORE</a> Its K.E.=1/2mV_0^2=^1//_2m(GM)/r=^1//_2(<a href="https://interviewquestions.tuteehub.com/tag/gmm-2090431" style="font-weight:bold;" target="_blank" title="Click to know more about GMM">GMM</a>)/(2.r)and it's ` PE(GMm)/rxxr/(GMm)=^1//_2`</body></html>
Discussion
45256.

There is no charge on 3F capacitor when .S. is open. Much heat (in Joule) is developed in circuit after .S. is closed ?

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/6-327005" style="font-weight:bold;" target="_blank" title="Click to know more about 6">6</a></body></html>
Discussion
45257.

In the circuit shown in the figure, if both the bulbs B_(1) and B_(2) are identical

Answer» <html><body><p>their brightness will be the same <br/>`B_(2)` will be greater than `B_(1)` <br/>as frequency of supply volatage is <a href="https://interviewquestions.tuteehub.com/tag/increased-1040402" style="font-weight:bold;" target="_blank" title="Click to know more about INCREASED">INCREASED</a> brightness of bulb `B_(1)` will increase and that of <a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a> decrease<br/>Brightness of both <a href="https://interviewquestions.tuteehub.com/tag/bulbs-905371" style="font-weight:bold;" target="_blank" title="Click to know more about BULBS">BULBS</a> is independent o frequency</p>Answer :B::<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>
Discussion
45258.

A rectangular coil of 20 turns and area of cross-section 25 square cm has a resistance of 100 ohm. If a magnetic field which is perpendicular to the coil change at a rate of 100 tesla per sec,the current in the coil is :

Answer» <html><body><p>1.0 <a href="https://interviewquestions.tuteehub.com/tag/ampere-374815" style="font-weight:bold;" target="_blank" title="Click to know more about AMPERE">AMPERE</a> <br/><a href="https://interviewquestions.tuteehub.com/tag/50-322056" style="font-weight:bold;" target="_blank" title="Click to know more about 50">50</a> ampere <br/>0.5 ampere<br/>5.0 ampere</p>Answer :<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>
Discussion
45259.

Watt is the unit of

Answer» <html><body><p>force<br/>pressure<br/>work <br/>power.</p>Answer :D</body></html>
Discussion
45260.

What is the shape of the wavefront in each of the following cases: (a) Light diverging from a point source. (b) Light emerging out of a convex lens when a point source is placed at its focus. (c) The portion of the wavefront of light from a distant star intercepted by the Earth.

Answer» <html><body><p></p>Solution :Wavefronts emitted from distant star and then <a href="https://interviewquestions.tuteehub.com/tag/propagating-2957671" style="font-weight:bold;" target="_blank" title="Click to know more about PROPAGATING">PROPAGATING</a> in three dimensional <a href="https://interviewquestions.tuteehub.com/tag/homogeneous-1028736" style="font-weight:bold;" target="_blank" title="Click to know more about HOMOGENEOUS">HOMOGENEOUS</a> and isotropic medium are found to be plane locally at very large distance from that star (i.e, on the <a href="https://interviewquestions.tuteehub.com/tag/earth-13129" style="font-weight:bold;" target="_blank" title="Click to know more about EARTH">EARTH</a>). <a href="https://interviewquestions.tuteehub.com/tag/hence-484344" style="font-weight:bold;" target="_blank" title="Click to know more about HENCE">HENCE</a> small portion of such wavefronts <a href="https://interviewquestions.tuteehub.com/tag/observed-582965" style="font-weight:bold;" target="_blank" title="Click to know more about OBSERVED">OBSERVED</a> from Earth will be "Plane Wavefronts".</body></html>
Discussion
45261.

Wavelength of radiations emitted, when an electron jumps from a state A to C is 2000 Å and it is 6000 Å, when the clectron jumps from state B to state C. Wavelength of the radiations emitted, when an electron jumps from state A to B will be:

Answer» <html><body><p><a href="https://interviewquestions.tuteehub.com/tag/2000-289566" style="font-weight:bold;" target="_blank" title="Click to know more about 2000">2000</a> Å<br/>3000 Å<br/>4000 Å<br/>6000 Å</p>Solution :<a href="https://interviewquestions.tuteehub.com/tag/use-1441041" style="font-weight:bold;" target="_blank" title="Click to know more about USE">USE</a> `lambda_(<a href="https://interviewquestions.tuteehub.com/tag/3-301577" style="font-weight:bold;" target="_blank" title="Click to know more about 3">3</a>)=(lambda_(<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>)+lambda_(2))/(lambda_(1)+lambda_(2))` <br/> Here `lambda_(3)=2000Å, lambda_(1)=6000Å," then "lambda_(2)=3000Å`</body></html>
Discussion
45262.

Large band width for higher data is achieved by using

Answer» <html><body><p>high <a href="https://interviewquestions.tuteehub.com/tag/frequency-465761" style="font-weight:bold;" target="_blank" title="Click to know more about FREQUENCY">FREQUENCY</a> carrier <a href="https://interviewquestions.tuteehub.com/tag/wave-22399" style="font-weight:bold;" target="_blank" title="Click to know more about WAVE">WAVE</a><br/>high frequency <a href="https://interviewquestions.tuteehub.com/tag/audio-887821" style="font-weight:bold;" target="_blank" title="Click to know more about AUDIO">AUDIO</a> wave <br/><a href="https://interviewquestions.tuteehub.com/tag/low-537644" style="font-weight:bold;" target="_blank" title="Click to know more about LOW">LOW</a> frequency carrier wave <br/>low frequency audio wave</p>Answer :A</body></html>
Discussion
45263.

A uniform rectangular block has length twice as large as the breath. It is lying on the horizontal plane, which is gradually being raised so as to be inclined to the horizontal at an angle theta. For what value theta, the block be at the point of toppling?

Answer» <html><body><p>`70.6^(@)`<br/>`65.8^(@)`<br/>`45.5^(@)`<br/>`26.6^(@)`</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> :The block will be at the verge of toppling if the vertical <a href="https://interviewquestions.tuteehub.com/tag/line-1074199" style="font-weight:bold;" target="_blank" title="Click to know more about LINE">LINE</a> from the centre of mass just passes from within its base <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/MOD_RPA_OBJ_PHY_C06_E01_001_S01.png" width="80%"/> <br/> `therefore <a href="https://interviewquestions.tuteehub.com/tag/tantheta-3098264" style="font-weight:bold;" target="_blank" title="Click to know more about TANTHETA">TANTHETA</a>=((a)/(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>))/(a)=0.5impliestheta=26.6^(@)`</body></html>
Discussion
45264.

For series combination total resistance R will be:

Answer» <html><body><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>)/(<a href="https://interviewquestions.tuteehub.com/tag/r-611811" style="font-weight:bold;" target="_blank" title="Click to know more about R">R</a>)=(1)/(R_(1))+(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>))+(1)/(R_(<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/>`R=R_(1)R_(2)R_(3) . . . . .`<br/>`R=(1)/(R_(1))+(1)/(R_(2))+(1)/(R_(3))+ . . . . .`<br/>`R=R_(1)+R_(2)+R_(3) + . . . .`</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> :D</body></html>
Discussion
45265.

A 10 kg box is placed on a surface. Coefficient of friction between surface and box is u = 0.5. Horizontal force of 100N is applied. Acceleration of block will be :

Answer» <html><body><p>`<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>.<a href="https://interviewquestions.tuteehub.com/tag/5-319454" style="font-weight:bold;" target="_blank" title="Click to know more about 5">5</a> m//s^(2)`<br/>`5 m//s^(2)`<br/>`7.5 m//s^(2)`<br/><a href="https://interviewquestions.tuteehub.com/tag/none-580659" style="font-weight:bold;" target="_blank" title="Click to know more about NONE">NONE</a> of these.</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>
Discussion
45266.

A block A of mass 6kg is applied on a frictionless table. A thread tied to it passes over a frictionless pulley and carries a body B of mass 4kg at the other end. Find the acceleration of the system and tension in the thread (given g=10ms^(-2))

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=4 m//s^(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>) , <a href="https://interviewquestions.tuteehub.com/tag/24-295400" style="font-weight:bold;" target="_blank" title="Click to know more about 24">24</a> <a href="https://interviewquestions.tuteehub.com/tag/n-568463" style="font-weight:bold;" target="_blank" title="Click to know more about N">N</a>`</body></html>
Discussion
45267.

Change in temperature

Answer» <html><body><p>increases <a href="https://interviewquestions.tuteehub.com/tag/forward-464460" style="font-weight:bold;" target="_blank" title="Click to know more about FORWARD">FORWARD</a> resistance<br/>decreases forward resistance<br/>affects `v-i` characteristics of `p-n` <a href="https://interviewquestions.tuteehub.com/tag/junction-526696" style="font-weight:bold;" target="_blank" title="Click to know more about JUNCTION">JUNCTION</a> diode<br/>does not <a href="https://interviewquestions.tuteehub.com/tag/affect-851195" style="font-weight:bold;" target="_blank" title="Click to know more about AFFECT">AFFECT</a> `v-i` characteristics of `p-n` junction diode.</p>Answer :<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>
Discussion
45268.

An isolated nucleus which was initially at rest, disintegrates into two nuclei due to internal nuclear forces and nogamma rays are produced. If the ratio of their kinetic energy is found to be

Answer» <html><body><p>&lt;<a href="https://interviewquestions.tuteehub.com/tag/p-588962" style="font-weight:bold;" target="_blank" title="Click to know more about P">P</a>&gt;<a href="https://interviewquestions.tuteehub.com/tag/ratio-13379" style="font-weight:bold;" target="_blank" title="Click to know more about RATIO">RATIO</a> of their de-broglie wavelength is `(sqrt(64))/(sqrt(27))` respectively<br/>Ratio of their <a href="https://interviewquestions.tuteehub.com/tag/speed-1221896" style="font-weight:bold;" target="_blank" title="Click to know more about SPEED">SPEED</a> is 64/27 respectively<br/>Ratio of their nuclear radius is 5/4 respectively<br/>None of these<br/></p>Solution :`P_(1)=P_(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>)=P` <br/> `m_(1)v_(1)=m_(2)v_(2)` <br/> `((P^(2))/(2m_(1)))//((P^(2))/(2m_(2)))=64/27` <br/> `(m_(2))/(m_(1))-64/27 =(v_(1))/(v_(2))` <br/> `(lambda_(1))/(lambda_(2))=(h//P_(1))/(h//P_(2))=1:1` <br/> `(R_(1))/(R_(2))=((A_(1))/(A_(2)))^(1//3)=3/4`</body></html>
Discussion
45269.

A shell, which is initially located at a distance of 40.4 m above a horizontal plane, is fired horizontally with a muzzle velocity of 285 m/s to strike a target on the horizontal plane. (a) How long does the projectile remain in the air? (b) At what horizontal distance from the firing point does the shell strike the plane? What are the magnitudes of the (c ) horizontal and (d) vertical components of its velocity as it strikes the ground?

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) `~~2.87s`, (<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a>) 818 m, ( <a href="https://interviewquestions.tuteehub.com/tag/c-7168" style="font-weight:bold;" target="_blank" title="Click to know more about C">C</a>) <a href="https://interviewquestions.tuteehub.com/tag/285brbr-1834110" style="font-weight:bold;" target="_blank" title="Click to know more about 285">285</a> m/s, (d) 28.1 m/s</body></html>
Discussion
45270.

Is the dispersive power independent on the angle of the prism? Give reason.

Answer» <html><body><p></p>Solution :Yes, it is. The <a href="https://interviewquestions.tuteehub.com/tag/dispersive-7675463" style="font-weight:bold;" target="_blank" title="Click to know more about DISPERSIVE">DISPERSIVE</a> <a href="https://interviewquestions.tuteehub.com/tag/power-2475" style="font-weight:bold;" target="_blank" title="Click to know more about POWER">POWER</a> of the material of a <a href="https://interviewquestions.tuteehub.com/tag/prism-1166613" style="font-weight:bold;" target="_blank" title="Click to know more about PRISM">PRISM</a> <a href="https://interviewquestions.tuteehub.com/tag/depends-948548" style="font-weight:bold;" target="_blank" title="Click to know more about DEPENDS">DEPENDS</a> only on the <a href="https://interviewquestions.tuteehub.com/tag/nature-1112013" style="font-weight:bold;" target="_blank" title="Click to know more about NATURE">NATURE</a> of the material.</body></html>
Discussion
45271.

Three point charge have been placed along the x axis at points A, B and C. Distance AB = BC. The field lines generated by the system is shown in figure. (a) Plot the variation of electric potential along x axis. Show potential on y axis of your graph. (b) Plot the variation of electric potential along y axis with B as origin. Shows potential on x axis in your graph.

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). Yes spherical <br/> (b). `(d)/(sqrt(<a href="https://interviewquestions.tuteehub.com/tag/3-301577" style="font-weight:bold;" target="_blank" title="Click to know more about 3">3</a>)-<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>)` <br/> (<a href="https://interviewquestions.tuteehub.com/tag/c-7168" style="font-weight:bold;" target="_blank" title="Click to know more about C">C</a>). `(2KQ)/(d)(2-sqrt(3))` <br/> (d) `(-Q)/(in_(0))`</body></html>
Discussion
45272.

The work function of a metal is 3.0 V. It is illuminated by a light of wave length 3xx10^(-7)m.Calculate i) threshold frequency, ii) the maximum energy of photoelectrons, iii) the stopping potential. (h=6.63xx10^(-34)Js and c=3xx10^(8)ms^(-)).

Answer» <html><body><p></p>Solution :`W=hv_(0)=3.0eV=3xx1.6xx10^(-19)J` <br/> <a href="https://interviewquestions.tuteehub.com/tag/threshold-1419373" style="font-weight:bold;" target="_blank" title="Click to know more about THRESHOLD">THRESHOLD</a> frequency <br/> `v_(0)=(W)/(<a href="https://interviewquestions.tuteehub.com/tag/h-1014193" style="font-weight:bold;" target="_blank" title="Click to know more about H">H</a>)=(3xx1.6xx10^(-19))/(6.63xx10^(-34))=0.72xx10^(15)Hz` <br/> (ii) Maximum kinetic energy `(E_(max))=h(v-v_(0))` <br/> `lamda-<a href="https://interviewquestions.tuteehub.com/tag/3xx10-1865443" style="font-weight:bold;" target="_blank" title="Click to know more about 3XX10">3XX10</a>^(-7)m,v=(c)/(lamda)=(3xx10^(8))/(3xx10^(-7))=1xx10^(15)Hz` <br/> `K_(max)=h(v-v_(0))` <br/> `=6.63xx10^(-34)(1-0.72)xx10^(15)J=1.86xx10^(-19)J`. <br/> (<a href="https://interviewquestions.tuteehub.com/tag/iii-497983" style="font-weight:bold;" target="_blank" title="Click to know more about III">III</a>) `K_(max)=eV_(0)` where `V_(0)` is stopping potential in volt and e is the charge of electron <br/> `V_(0)=(K_(max))/(e)`. Here `K_(max)=1.86xx10^(-19)J` and `e=1.6xx10^(-19)C" "V_(0)=(1.86xx10^(-19)J)/(1.6xx10^(-19)C)=1.16V`</body></html>
Discussion
45273.

A: Diamond glitters.R: Diamond doesn.t absorb sun light.

Answer» <html><body><p>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 <a href="https://interviewquestions.tuteehub.com/tag/reason-620214" style="font-weight:bold;" target="_blank" title="Click to know more about REASON">REASON</a> are <a href="https://interviewquestions.tuteehub.com/tag/true-713260" style="font-weight:bold;" target="_blank" title="Click to know more about TRUE">TRUE</a> and the reason is <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> of the assertion.<br/>Both assertion and reason are true but reason is not correct explanation of the assertion<br/>Assertion is true but the reason is false.<br/>Both assertion and reason are false.</p>Solution :Both assertion and reason are true but reason is not correct explanation of the assertion</body></html>
Discussion
45274.

A plane progressive wave of frequency 25Hz amplitude 2.5 xx 10^(-5) m and initial phase zero propagates along negative x-direction with a Velocity of 300 m/s. At any instant, the phase difference between the oscillations at two points 6m apart along the line is phi and the corresponding amplitude difference is A.

Answer» <html><body><p>A=0<br/>`phi=0`<br/>`A = 2.5 <a href="https://interviewquestions.tuteehub.com/tag/xx-747671" style="font-weight:bold;" target="_blank" title="Click to know more about XX">XX</a> <a href="https://interviewquestions.tuteehub.com/tag/10-261113" style="font-weight:bold;" target="_blank" title="Click to know more about 10">10</a>^(-5) m`<br/>`phi = pi`</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::D</body></html>
Discussion
45275.

Find the value of magnetic dipole moment (in Am^(2)) of the following circuit the current distribution is shown in the diagram.

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> :`vecM_(<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>)+vecM_(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>)=M=4r^(2)<a href="https://interviewquestions.tuteehub.com/tag/hati-2693493" style="font-weight:bold;" target="_blank" title="Click to know more about HATI">HATI</a>` <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/FIT_JEE_PHY_GMP_ASS_E01_059_S01.png" width="80%"/></body></html>
Discussion
45276.

In Figure, two isotropic point sources S_(1) and S_(2) emit light in phase at wavelength lambda and at the same amplitude. The sources are separated by distance 2d = 6.00 lambda. They lie on an axis that is parallel to an x axis, which runs along a viewing screen at distance D = 20.0 lambda. The origin lies on the perpendicular bisector between the sources. The figure shows two rays reaching point P on the screen, at position x_(P). (a) At what value of x_(P) do the rays have the minimum possible phase difference? (b) What multiple of lambda gives that minimum phase difference? (c) At what value of x_(P) do the rays have the maximum possible phase difference? What multiple of lambda gives (d) that maximum phase difference and (c) the phase difference when x_(P)=6.00 lambda? (f) When x_(P)=6.00 lambda, is the resulting intensity at point P maximum, minimum, intermediate but closer to maximum, or intermediate but closer to minimum?

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) 0, (<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a>) 0, (C) `infty`, (d) 12p, (e) 3.6p, (<a href="https://interviewquestions.tuteehub.com/tag/f-455800" style="font-weight:bold;" target="_blank" title="Click to know more about F">F</a>) “intermediate” but <a href="https://interviewquestions.tuteehub.com/tag/closer-7270227" style="font-weight:bold;" target="_blank" title="Click to know more about CLOSER">CLOSER</a> to a <a href="https://interviewquestions.tuteehub.com/tag/minimum-561095" style="font-weight:bold;" target="_blank" title="Click to know more about MINIMUM">MINIMUM</a> than to a maximum</body></html>
Discussion
45277.

If sound waves of frequency 20 KHz are to transmitted directly, then the length of the anternna required is :

Answer» <html><body><p>3.75 km<br/>15 km<br/>7.5 km<br/>20 km</p>Answer :<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>
Discussion
45278.

A long straight wire carries a current of 35 A. What is the magnitude of the field B at a point 20 cm from the wire?

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> :`3.<a href="https://interviewquestions.tuteehub.com/tag/5-319454" style="font-weight:bold;" target="_blank" title="Click to know more about 5">5</a> <a href="https://interviewquestions.tuteehub.com/tag/xx-747671" style="font-weight:bold;" target="_blank" title="Click to know more about XX">XX</a> <a href="https://interviewquestions.tuteehub.com/tag/10-261113" style="font-weight:bold;" target="_blank" title="Click to know more about 10">10</a>^(-5) T`</body></html>
Discussion
45279.

The radioactivity of given sample of whisky due to tritium (half life = 12 yrs) was found to be only 3.125% of that measured in a recently purchased bottle marked "10 yrs old". By how many years ago sample must have been prepared ?

Answer» <html><body><p>20 yrs<br/>30 yrs<br/>50 yrs<br/>70 yrs</p>Solution :`A/A_(0)=(1/2)^(t/T) rArr (3.125)/(<a href="https://interviewquestions.tuteehub.com/tag/100-263808" style="font-weight:bold;" target="_blank" title="Click to know more about 100">100</a>) =(1/2)^(t/T)` <br/> `rArr (1)/(32)=(1/2)^(t/T) rArr (1/2)^(5) =(1/2)^(t/T)` <br/> `t=5T =5 <a href="https://interviewquestions.tuteehub.com/tag/xx-747671" style="font-weight:bold;" target="_blank" title="Click to know more about XX">XX</a> 12=60yrs` <br/> <a href="https://interviewquestions.tuteehub.com/tag/total-711110" style="font-weight:bold;" target="_blank" title="Click to know more about TOTAL">TOTAL</a> <a href="https://interviewquestions.tuteehub.com/tag/age-851457" style="font-weight:bold;" target="_blank" title="Click to know more about AGE">AGE</a> of sample `=60+10=70yrs`</body></html>
Discussion
45280.

Thermal radiations are electromagnetic radiation belonging to

Answer» <html><body><p><a href="https://interviewquestions.tuteehub.com/tag/visible-1447103" style="font-weight:bold;" target="_blank" title="Click to know more about VISIBLE">VISIBLE</a> region<br/>ultra <a href="https://interviewquestions.tuteehub.com/tag/violet-1446649" style="font-weight:bold;" target="_blank" title="Click to know more about VIOLET">VIOLET</a> region<br/>infra <a href="https://interviewquestions.tuteehub.com/tag/red-613739" style="font-weight:bold;" target="_blank" title="Click to know more about RED">RED</a> region<br/>X-ray region</p>Answer :<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>
Discussion
45281.

Calculate the energy equivalent of 1 atomic mass unit.

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> :We take,m = 1 amu = `1.66 xx 10^(-27)` kg <br/> `<a href="https://interviewquestions.tuteehub.com/tag/c-7168" style="font-weight:bold;" target="_blank" title="Click to know more about C">C</a> = <a href="https://interviewquestions.tuteehub.com/tag/3-301577" style="font-weight:bold;" target="_blank" title="Click to know more about 3">3</a> xx 10^(8) ms^(-1)` <br/> Then, `E = mc^(2) = 1.66 xx 10^(-27) xx(3 xx (10)^(8))^(2)`J <br/> ` = (1.66 xx 10^(-27) xx(3 xx10^(8))^(2))/(1.6 xx 10^(-19)) eV` <br/> `E approx 981` <a href="https://interviewquestions.tuteehub.com/tag/mev-557539" style="font-weight:bold;" target="_blank" title="Click to know more about MEV">MEV</a> <br/> `therefore` 1 amu = 931 MeV</body></html>
Discussion
45282.

Calculate mass percentage of Sulphur in Sulphur dioxide is

Answer» <html><body><p>`<a href="https://interviewquestions.tuteehub.com/tag/47-317855" style="font-weight:bold;" target="_blank" title="Click to know more about 47">47</a>%`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/27-298706" style="font-weight:bold;" target="_blank" title="Click to know more about 27">27</a>%`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/50-322056" style="font-weight:bold;" target="_blank" title="Click to know more about 50">50</a>%`<br/>`44.8%`</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>
Discussion
45283.

The graph between frequency v of k. X-rays and the atomic number Z

Answer» <html><body><p><a href="https://interviewquestions.tuteehub.com/tag/straight-633156" style="font-weight:bold;" target="_blank" title="Click to know more about STRAIGHT">STRAIGHT</a> <a href="https://interviewquestions.tuteehub.com/tag/line-1074199" style="font-weight:bold;" target="_blank" title="Click to know more about LINE">LINE</a> <br/><a href="https://interviewquestions.tuteehub.com/tag/parabola-1146268" style="font-weight:bold;" target="_blank" title="Click to know more about PARABOLA">PARABOLA</a> <br/>Ellipse<br/>Circle </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>
Discussion
45284.

From the output characteristic shown in fig.calculate the value of current amplification factor of the transistor when V_(CE)=2 V.

Answer» <html><body><p></p>Solution :From the <a href="https://interviewquestions.tuteehub.com/tag/given-473447" style="font-weight:bold;" target="_blank" title="Click to know more about GIVEN">GIVEN</a> <a href="https://interviewquestions.tuteehub.com/tag/characteristic-914243" style="font-weight:bold;" target="_blank" title="Click to know more about CHARACTERISTIC">CHARACTERISTIC</a>, corresponding to `V_(CE)=2.0V`, note the collector current for two base current (<a href="https://interviewquestions.tuteehub.com/tag/say-1195451" style="font-weight:bold;" target="_blank" title="Click to know more about SAY">SAY</a> `50muA` and `200muA)`. The corresponding values of` I_c` are `3.0mA` and `9.0mA` <a href="https://interviewquestions.tuteehub.com/tag/respectively-1186938" style="font-weight:bold;" target="_blank" title="Click to know more about RESPECTIVELY">RESPECTIVELY</a>. <br/> Then `DeltaI_c=9-3=6mA, DeltaI_b=200-50=150muA` <br/> `:.` Current amplification <a href="https://interviewquestions.tuteehub.com/tag/factor-458892" style="font-weight:bold;" target="_blank" title="Click to know more about FACTOR">FACTOR</a>, `beta_(ac)=(DeltaI_c)/(DeltaI_b)=(6mA)/(150muA)=40`</body></html>
Discussion
45285.

A block is gently placed on a conveyor belt moving horizontally with constant speed. After t = 4s, the velocity of the block becomes equal to the velocity of the belt. If the coefficient of friction between the block and the belt is mu = 0.2, then the velocity of the conveyor belt is (g= 10ms^(-2))

Answer» <html><body><p>`<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a> ms^(-1)`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/4-311707" style="font-weight:bold;" target="_blank" title="Click to know more about 4">4</a> ms^(-1)`<br/>`64ms^(-1)`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/8-336412" style="font-weight:bold;" target="_blank" title="Click to know more about 8">8</a> ms^(-1)`</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> :D</body></html>
Discussion
45286.

When Iron nail is dipped in Copper Sulphate solution

Answer» <html><body><p>Blue <a href="https://interviewquestions.tuteehub.com/tag/color-922196" style="font-weight:bold;" target="_blank" title="Click to know more about COLOR">COLOR</a> <a href="https://interviewquestions.tuteehub.com/tag/changes-913881" style="font-weight:bold;" target="_blank" title="Click to know more about CHANGES">CHANGES</a> to green<br/>Red brown <a href="https://interviewquestions.tuteehub.com/tag/layer-1069875" style="font-weight:bold;" target="_blank" title="Click to know more about LAYER">LAYER</a> of copper metal on iron nail.<br/>Blue color remains as it is<br/>Both A &amp; B</p>Answer :A</body></html>
Discussion
45287.

A blackened platinum wire is of length 0.1 m and circumference 2 xx 10^(-4) m. calculate the rate at which the wire is loosing energy if it's temperature is 3000 K .

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> :Rate of loss energy = `<a href="https://interviewquestions.tuteehub.com/tag/e-444102" style="font-weight:bold;" target="_blank" title="Click to know more about E">E</a> sigma T^4 <a href="https://interviewquestions.tuteehub.com/tag/xx-747671" style="font-weight:bold;" target="_blank" title="Click to know more about XX">XX</a> A` <br/> Here e = 1 (blackened surface), <br/> `sigma = 5.67 xx 10^(-8) <a href="https://interviewquestions.tuteehub.com/tag/j-520843" style="font-weight:bold;" target="_blank" title="Click to know more about J">J</a> m^(-2) s^(-1) k^(-4)` <br/> T= <a href="https://interviewquestions.tuteehub.com/tag/3000k-1852552" style="font-weight:bold;" target="_blank" title="Click to know more about 3000K">3000K</a> <br/> A = `(2 pi r) xx l = 2 pi (2 xx 10^(-4) ) xx 0.1 m^2`.</body></html>
Discussion
45288.

Two particle X and Y having equal charge, after being accelerated through the same potential difference enter a region of uniform magnetic field and describe circular paths of radii R_1 and R_2 respectively. The ratio of the mass of X to that of Y is

Answer» <html><body><p>`(r_1)/(r_2)`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/sqrt-1223129" style="font-weight:bold;" target="_blank" title="Click to know more about SQRT">SQRT</a>((r_1)/(r_2))`<br/>`[(r_2)/(r_1)]^(<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/>`[(r_1)/(r_2)]^(2)`</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> :D</body></html>
Discussion
45289.

Crystal diffraction experiments can be performed using X-rays, or electrons accelerated through appropriate voltage. Which probe has greater energy ? (For quantitative comparison, take the wavelength of the probe equal to 1 Å, which is of the order of inter-atomic spacing in the lattice) (m_(e)=9.11xx10^(-31)kg).

Answer» <html><body><p></p>Solution :It is given here that wavelength of probe `lamda=1Å=1xx10^(-<a href="https://interviewquestions.tuteehub.com/tag/10-261113" style="font-weight:bold;" target="_blank" title="Click to know more about 10">10</a>)m` <br/> When we use X-rays as the probe, the energy of X-ray photon <br/> `E_("X-ray")=hv=(hc)/(lamda)=(6.63xx10^(-34)xx3xx10^(<a href="https://interviewquestions.tuteehub.com/tag/8-336412" style="font-weight:bold;" target="_blank" title="Click to know more about 8">8</a>))/(1xx10^(-10))J=(6.63xx10^(-34)xx3xx10^(8))/(1xx10^(-10)xx1.6xx10^(-19))eV=12.4xx10^(3)eV=12.4keV` <br/> When <a href="https://interviewquestions.tuteehub.com/tag/electron-968715" style="font-weight:bold;" target="_blank" title="Click to know more about ELECTRON">ELECTRON</a> waves are used as the probe, the energy of an electron <br/> `E_("electron")=(1)/(2)mv^(2)=(p^(2))/(2m)=(1)/(2m)(h^(2))/(lamda^(2))=((6.63xx10^(-34))^(2))/(2xx.911xx10^(-<a href="https://interviewquestions.tuteehub.com/tag/31-306830" style="font-weight:bold;" target="_blank" title="Click to know more about 31">31</a>)xx(1xx10^(-10))^(2))`J <br/> `=((6.63xx10^(-34))^(2))/(2xx9.11xx10^(-31)xx(10^(-10))^(2)xx1.6xx10^(-19))eV=150eV` <br/> A <a href="https://interviewquestions.tuteehub.com/tag/simple-1208262" style="font-weight:bold;" target="_blank" title="Click to know more about SIMPLE">SIMPLE</a> comparison of two answers shows `E_("X-ray")gtgtE_("electron")`.</body></html>
Discussion
45290.

A magnet of magnetic dipole moment M is released in a uniform magnetic field of induction B from the position shown in the figure.Find (i) Its kinetic energy at theta=90^(@) (ii)its maximum kinetic energy during the motion. (iii) will it perform SHM? oscillation? Periodic motion? What is its amplitude ?

Answer» <html><body><p></p>Solution :(i) Apply energy conservation at `theta=120^(@)` and `theta=90^(@)` <br/> `-<a href="https://interviewquestions.tuteehub.com/tag/mb-546939" style="font-weight:bold;" target="_blank" title="Click to know more about MB">MB</a> cos 120^(@)+<a href="https://interviewquestions.tuteehub.com/tag/0-251616" style="font-weight:bold;" target="_blank" title="Click to know more about 0">0</a>` <br/> `=-MB cos 90^(@)+(K.E)` <br/> `<a href="https://interviewquestions.tuteehub.com/tag/ke-527890" style="font-weight:bold;" target="_blank" title="Click to know more about KE">KE</a>=(MB)/2` <br/> (ii) `K.E.` will be maximum where `P.E.` is minimum. `P.E` is minimum at `theta=0^(@)`.Now apply energy conservation between `theta=120^(@)` and `theta=0^(@)` <br/> `-mB cos 120^(@)+0` <br/> `=-mB cos 0^(@)+(K.E)_(max)` <br/> `(KE)_(max)=3/2MB` <br/> The `K.E` is max at `theta=0^(@)` can also be proved by torque method.From `theta=120^(@)` to `theta=0^(@)` the torque always <a href="https://interviewquestions.tuteehub.com/tag/acts-848461" style="font-weight:bold;" target="_blank" title="Click to know more about ACTS">ACTS</a> on the dipole in the same direction (here it is clockwise) so its `K.E.` keeps on increase till `theta=0^(@)`, Beyond that reverses its direction and then `K.E.` starts decreasing <br/> `:. theta=0^(@)` is the orientation of `M` to here the maximum `K.E.` <br/> (iii) Since `theta` is not small. <br/> `:.`the motion is not `S.H.M` but it is <a href="https://interviewquestions.tuteehub.com/tag/oscillatory-2208020" style="font-weight:bold;" target="_blank" title="Click to know more about OSCILLATORY">OSCILLATORY</a> and periodic amplitude is `120^(@)`</body></html>
Discussion
45291.

A magnet is quickly moved in the direction indicated by an arrow between two coils C_(1) and C_(2) as shown in the Fig. 6.34. What will be the direction of induced current in each coil as seen from the magnet ? Justify you answer.

Answer» <html><body><p></p>Solution :In the figure, the magrant NS, with its N-pole facing coil `C_(1)`, is moving away from the coil `C_(1)`. Hence, in accordance with Lenz.s law the <a href="https://interviewquestions.tuteehub.com/tag/induced-1042496" style="font-weight:bold;" target="_blank" title="Click to know more about INDUCED">INDUCED</a> current will flow in clockwise <a href="https://interviewquestions.tuteehub.com/tag/direction-1696" style="font-weight:bold;" target="_blank" title="Click to know more about DIRECTION">DIRECTION</a> when seen from the magnet. In such a situation face of coil `C_(1)` facing N-pole of magnet will <a href="https://interviewquestions.tuteehub.com/tag/develop-431630" style="font-weight:bold;" target="_blank" title="Click to know more about DEVELOP">DEVELOP</a> S <a href="https://interviewquestions.tuteehub.com/tag/polarity-1157527" style="font-weight:bold;" target="_blank" title="Click to know more about POLARITY">POLARITY</a> and will oppose the motion of magnet away from the coil `C_(1)`. <br/> Again the magnet NS, with its S-pole facing coil `C_(2)`, is moving towards the coil `C_(2)`. Hence in accordance with Lenz.s law, the induced current will flow in clockwise direction when seen from me magnet. In such a situation, face of coil `C_(2)` facing S-pole of magnet will develop a Spolarity and will oppose the motion of magnet towards the coil `C_(2).`</body></html>
Discussion
45292.

A point source of light is 60 cm from a screen and is kept at the focus of a concave mirror which reflects light on the screen. The focal length of the mirror is 20 cm. The ratio of average intensities of the illumination on the screen when the mirror is present and when the mirror is removed is

Answer» <html><body><p>`36:1`<br/>`37:1` <br/>`49:1`<br/>`10:1`</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> :D</body></html>
Discussion
45293.

The figure shows the various positionsof smallmagnetised needles P and Q the arrows show thedirectionof theirmagnetic moment whichlowest potenticalenergy amongallthe configurationshown?

Answer» <html><body><p>`PQ_(3)`<br/>`PQ_(4)`<br/>`PQ_(5)`<br/>`PQ_(6)` </p>Solution :`PQ_(6)`corresponds to the lowest <a href="https://interviewquestions.tuteehub.com/tag/potential-1161228" style="font-weight:bold;" target="_blank" title="Click to know more about POTENTIAL">POTENTIAL</a> <a href="https://interviewquestions.tuteehub.com/tag/energy-15288" style="font-weight:bold;" target="_blank" title="Click to know more about ENERGY">ENERGY</a> <a href="https://interviewquestions.tuteehub.com/tag/among-374776" style="font-weight:bold;" target="_blank" title="Click to know more about AMONG">AMONG</a> all the <a href="https://interviewquestions.tuteehub.com/tag/configuration-11827" style="font-weight:bold;" target="_blank" title="Click to know more about CONFIGURATION">CONFIGURATION</a> <a href="https://interviewquestions.tuteehub.com/tag/show-642916" style="font-weight:bold;" target="_blank" title="Click to know more about SHOW">SHOW</a></body></html>
Discussion
45294.

Distinguish between resistance, reactance and impedance of an a.c. circuit ?

Answer» <html><body><p></p>Solution :Resistance : It is the opposition <a href="https://interviewquestions.tuteehub.com/tag/offered-7257483" style="font-weight:bold;" target="_blank" title="Click to know more about OFFERED">OFFERED</a> by a pure resister to the flow of <a href="https://interviewquestions.tuteehub.com/tag/current-940804" style="font-weight:bold;" target="_blank" title="Click to know more about CURRENT">CURRENT</a> in a circuit. <br/> Reactance : The non-resistive opposition to the flow of current is called reactance.<br/> <a href="https://interviewquestions.tuteehub.com/tag/impedance-1037707" style="font-weight:bold;" target="_blank" title="Click to know more about IMPEDANCE">IMPEDANCE</a> : It is <a href="https://interviewquestions.tuteehub.com/tag/effective-966090" style="font-weight:bold;" target="_blank" title="Click to know more about EFFECTIVE">EFFECTIVE</a> resistance of an a.c. circuit containing any two or all the three elements R.L.C.</body></html>
Discussion
45295.

A source of light is placed at a distance of 50 cm from a photocell and the stopping potential is found to be V_0 .If the distance between the light source and photocell is made 25 cm, the new stopping potential will be

Answer» <html><body><p>`2V_0` <br/>`V_0//2`<br/>`V_0` <br/>`4V_0` </p>Solution :<a href="https://interviewquestions.tuteehub.com/tag/since-644476" style="font-weight:bold;" target="_blank" title="Click to know more about SINCE">SINCE</a> , stopping potential is <a href="https://interviewquestions.tuteehub.com/tag/independent-505826" style="font-weight:bold;" target="_blank" title="Click to know more about INDEPENDENT">INDEPENDENT</a> of distance hence <a href="https://interviewquestions.tuteehub.com/tag/new-1114486" style="font-weight:bold;" target="_blank" title="Click to know more about NEW">NEW</a> stopping potential will remain <a href="https://interviewquestions.tuteehub.com/tag/unchanged-2316761" style="font-weight:bold;" target="_blank" title="Click to know more about UNCHANGED">UNCHANGED</a> i.e., neq stopping potential ` = V_0`</body></html>
Discussion
45296.

The electron in a hydrogen atom revolves in an orbit of radius 0.5 Å, constituting a conventional current of 1.1 mA. Calculate the magnetic induction at an axial point 100 Å from the nucleus of theatom.

Answer» <html><body><p></p>Solution :Data: `r=<a href="https://interviewquestions.tuteehub.com/tag/0-251616" style="font-weight:bold;" target="_blank" title="Click to know more about 0">0</a>.5 Å= 5 xx 10^(-11), I=1.1 xx 10^(-3) A, <a href="https://interviewquestions.tuteehub.com/tag/x-746616" style="font-weight:bold;" target="_blank" title="Click to know more about X">X</a>=100 Å= 10^(-<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, (mu_(0))/(4pi) = 10^(-7) T.m//A` <br/> The magnitude of the magnetic induction at an axial point of a current loop, <br/> `B=(mu_(0))/(4pi). (2IA)/(r^(2) + x^(2))^(3//2) ~= (mu_(0))/(4pi)(2IA)/(x^(3))(therefore x^(2) <a href="https://interviewquestions.tuteehub.com/tag/gt-1013864" style="font-weight:bold;" target="_blank" title="Click to know more about GT">GT</a> gt R^(2))` <br/> `=(mu_(0))/(4pi)(2I(pir^(2)))/(x^(3))` <br/> `=(10^(-7))(2(1.1 xx 10^(-3))(3.142)(5 xx 10^(-11))^(2))/(10^(-8))^(3)` <br/> `=3.142 xx 55 xx 10^(-8) = 1.728 xx 10^(-6)` T</body></html>
Discussion
45297.

The work function for a certain metal is 4.2 eV. Will this metal give photoelectric emission for incident radiation of wavelength 330 nm?

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> :No. because `<a href="https://interviewquestions.tuteehub.com/tag/v-722631" style="font-weight:bold;" target="_blank" title="Click to know more about V">V</a> <a href="https://interviewquestions.tuteehub.com/tag/lt-537906" style="font-weight:bold;" target="_blank" title="Click to know more about LT">LT</a> v_(o)`</body></html>
Discussion
45298.

A direct vision spectroscope consists of three crown glass prism and two dense flint glass prisms placed alternately with their refracting edges turned in opposite directions. Calculate the net dispersion produced by the prisms. Angle of flint glass prism=10^(@) Numerical Examples in Physics {:(,"Crown glas"," Flint glass"),(mu ("red"),1.513,1.645),(mu("blue"),1.523,1.665):}

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> :8'49''</body></html>
Discussion
45299.

The mass of ""_(17)^(35)Cl is 34.9800 u . Calculate its binding energy per nucleon.

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> :8.2 <a href="https://interviewquestions.tuteehub.com/tag/mev-557539" style="font-weight:bold;" target="_blank" title="Click to know more about MEV">MEV</a></body></html>
Discussion
45300.

A person walks up a stationary excalator in time tl. If he remains stationary on the escalator, then it can take him up in time t_(2). How much time would it take him to walk up the moving escalator?

Answer» <html><body><p></p>Solution :Let <a href="https://interviewquestions.tuteehub.com/tag/l-535906" style="font-weight:bold;" target="_blank" title="Click to know more about L">L</a> be the length of ascalator. <a href="https://interviewquestions.tuteehub.com/tag/speed-1221896" style="font-weight:bold;" target="_blank" title="Click to know more about SPEED">SPEED</a> of man w.r.t esacalator is `v_(me)=(L)/(t_(1))`. Speed of escalator `v_(<a href="https://interviewquestions.tuteehub.com/tag/e-444102" style="font-weight:bold;" target="_blank" title="Click to know more about E">E</a>)=(L)/(t_(2))` <br/> Speed of man with respect to <a href="https://interviewquestions.tuteehub.com/tag/ground-1013213" style="font-weight:bold;" target="_blank" title="Click to know more about GROUND">GROUND</a> would be `v_(m)+v_(me)+v_(e)=L((1)/(t_(1))+(1)/(t_(2)))` <br/> `:.` The desired time is `t=(L)/(v_(m))=(t_(1)t_(2))/(t_(1)+t_(2))`</body></html>
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