45406 + Interview Questions in Physics in Class 12 Page 96 InterviewSolution

4751.	In an AC circuit the applied potential difference and the current flowing are given by : V = 200 sin 100 t volt, I= 5sin(100t +(pi)/(2))amp The power consumption is equal to :
Answer» 1000W 40 W 20 W zero Answer :D

Discussion

4752.	Up to what temperature has one to heat classiacal electronic gas to make the mean enrgy of its electrons equal to that of free electrons in copper at T=0? Only one free electron is supposed to correspond to each other atom.
Answer» Solution :The MEAN `K.E` of ELECTRONS in a Fermi gas is `(3)/(5)E_(F)`. This muat equal `(3)/(2)kT`. Thus `T=(2E_(F))/(5k)` we calculate, `E_(F)` FIRST. For `C_(U)` `n=(N_(A))/(M//rho)=(rhoN_(A))/(M)= "8.442xx10^(22)per c.c` Then `E_(F)= 7.01eV` and `T= 3.25xx10^(4)K`

Discussion

4753.	An alpha particle, a proton and an electron are moving with equal kinetic energy. Which one of these particles has the longest de Broglie wavelength? Give reason.
Answer» SOLUTION :`LAMDA= (h)/(SQRT(2mE)), lamda prop (1)/(sqrtm)` `m_(alpha) gt m_(p) gt m_(E )` `lamda_(e ) gt lamda_(p) gt lamda_(alpha)` `therefore` electron has longest wavelength, because of smaller MASS.

Discussion

4754.	Assertion In Young's double slit experiment, often both the phenomena interference and diffraction are present Reason Diffraction results due to superposition of wavelets from different points of the some wavefront
Answer» ANSWER :B

Discussion

4755.	All components of the electromagnetic spectrum in vaccum have the same
Answer» energy VELOCITY wavelength frequency Solution :All components of electromagnetic SPECTRUM travel in vacum with velocity `3 xx 10^(8) m/s`

Discussion

4756.	11xx10^(11) photons are incident on a surface in 100s.These photons correspond to a wavelength of 10Å .If the surface area of the given surface is 0.01 m^(2) ,the intensity of given radiations is ………(velocity of light is 3xx10^(8)ms^(-1),h=6.625x10^(-34)JS)
Answer» Solution :Number of photons incident in 10s=`11xx10^(11)` `therefore` Number of photons incident in 1 s`=11xx10^(10)` Now ,these photons being incident on area `0.01m^(2)` Number of photons being incident on `1m^(2)` in 1 s, `n=(11xx10^(10))/(0.01)` `=(11xx10^(10))/(10^(-2))=11xx10^(12)` Energy associated with n photons,`=(11xx10^(10)xx6.6xx10^(-34)xx3xx10^(8))/(10xx10^(-10))` `therefore` Intensity of incident radiation `=2.18xx10^(-3)Wm^(-2)`

Discussion

4757.	How can you calculate the amount of heat received (or delivered) by a system, using the T-S diagram?
Answer» Solution :By definition , `Delta S= (DeltaQ)/T`, therefore a small QUANTITY of heat `DeltaQ = T DeltaS` (see fig.) The total quantity of heat in the process is numerically EQUAL to the area of the curvilinear trapezoid shown in the figure (to the specified SCALE). The problem may be solved by NUMERICAL METHODS or by integration.

Discussion

4758.	For a given photosensitive material and with a source of constant frequency of incident radiation, how does the photocurrent vary with the intensity of incident light ?
Answer» Solution :For a given photosensitive material and with a source of constant frequency `V(vgtv_(0))` of INCIDENT radiation, the photocurrent INCREASES with increase in intensity of incident light.

Discussion

4759.	In a metere bridge, the balance length from left end (standard resistance of 1 Omegais in theright gap) is found to be 20cm the length of resistance in left gap is 1/2 m and radius is 2mm its specific resistance is
Answer» `PI xx 10^(-6)ohm -m` `2 pi xx 10^(-6)ohm -m` `(pi)/(2)xx 10^(-6)ohm -m` `3pi xx 10^(-6) ohm -m` ANSWER :B

Discussion

4760.	The centripetal acceleration of an electron in a Bohr's orbit is proportional to:
Answer» `1/n` `1/n^2` `1/n^3` `1/n^4` ANSWER :D

Discussion

4761.	Assertion: Standard optical diffraction can not beusedfordiscriminating between different X-rays wavelength. Reason: The grating spacing is not of the order of X-rays wavelengths.
Answer» If both assertion and REASON are true and reason is the correct explanation of assertion If both assertion and reason are true but reason is not the correct explanation of assertion. If assertion is true statement but resaon is false. If both assertion and reason are false. Solution :`X`-rays are electromagnetic radiations whose wavelength are of the order of `1 Å(=10^(-10)m)`. A standard optical DIFFRACTION grating cannot be USED to discriminate between different WAVELENGTHS in the `X`-rays wavelength range. For `i=1Å (= 0.1 nm)` and `d= 3000nm`, for example, the first order maximum occurs at, `theta= sin^(-1)((m lambda)/(d))= sin^(-1).((1) (0.1))/(3000)= 0.0019^(@)` This is to close to the central maximum to be practical. A grating with `d= lambda` is desirable, but since, `X`-rays wavelengths are about equal to ATOMIC diameter, such gratings cannot be constructed directly. Hence, option(a) is correct.

Discussion

4762.	In the circuit shown in figure, if the diode forward voltage drop is 0.3 V, the voltage difference between A and B is
Answer» 1.3 V 2.3 V 0 0.5 V Solution :2.3 V In above figure, calculating changes in electric potential during journey from POINT A to point B, `V_(A)-(0.2xx10^(-3)xx5xx10^(3))-0.3-(0.2xx10^(-3)xx5xx10^(3))=V_(B)` `therefore V_(A)-V_(B)=1+0.3+1=2.3V`

Discussion

4763.	White light is used to illuminate two slits in a YDSE. The separation between the slits is d and the screen is at a distance D(D gt gt d) from the slits. At a point on the screen direcrtly in front of one of the slits, which of the following wavelengths are missing.
Answer» `(B^(2))/(D)` `(2B^(2))/(D)` `(b^(2))/(3D)` `(2b^(2))/(3D)` Answer :A::C

Discussion

4764.	You are given two concave mirrors of different aperture sizes. Which one of the two you may select to get a sharper image?
Answer» Solution :Mirror with SMALLER APERTURE. Even though it can not collect MUCH LIGHT as the other one, it is free from spherical ABERRATION.

Discussion

4765.	In satellite communication 1. The frequency used lies between 5 MHz and 10 MHz. 2.The uplink and downlink frequencies are different. 3. The orbit of geostationary satellite lies in the equatorial plane at an inclination of 0^(@)
Answer» only 2 and 3 TRUE all are true only 2 true only 1 and 2 true ANSWER :A

Discussion

4766.	Resolving power of an optical instrument is associated with :
Answer» Diffraction polarisation Scattering of light Interference Answer :A

Discussion

4767.	According to the author what was garbage for the parents?
Answer» MEANS of entertainment Means of joy Means of sorrow Means of survival Answer :D

Discussion

4768.	Ratio of intensities of two waves are given by 4:1. Then ratio of the amplitudes of the two waves is
Answer» `2:1` `1:2` `4:1` `1:4` SOLUTION :`(I_(1))/(I_(2))=(a_(1)^(2))/(a_(2)^(2))=(4)/(1)` `:.(a_(1))/(a_(2))=(2)/(1)=2:1`

Discussion

4769.	If vec A =2 hat i+ 3 hat j+ 8 hat k is perpendicular to vec B= 4 hat j -4 hat i+ alpha hat k, then the value of alpha
Answer» `(1)/(2)` `-(1)/(2)` 1 `-1` SOLUTION :Given : `A=2HAT(i)+3hat(J)+8hat(k)` `B=4hat(j)-4hat(i)+alpha HAT(k)` `=-4hat(i)+4hat(j)+alpha hat(k)` `A _\|_ B` Hence, A. B = 0 `rArr (2hat(i)+3hat(j)+8hat(k))(-4hat(i)+4hat(j)+alpha hat(k))=0` `rArr -8+12+8alpha=0` `rArr 8alpha + 4=0` `rArr 8alpha =-4` `alpha =-(4)/(8)=-(1)/(2)`

Discussion

4770.	A long current carrying wire, carrying current such that it is flowing out from the plane of paper, is placed at O. A steady state current is flowing in the loop ABCD. Then,
Answer» the net force is zero the net torque is zero as SEEN from O, the loop will rotate in CLOCKWISE DIRECTION ALONG axis OO' as seen from O, the loop will rotate in anticlockwise direction along axis OO' Solution :Net force on AB and CD will zero because magnetic field due to `I_1` is along these parts. Force on BC due to `I_1` will be outwards and on AD will be inward. This will provide clockwise torque as seen form O.

Discussion

4771.	A wooden cylindricalof diameter 4r, heighth and density rho//3 is kepton a holeof diameter 2rof a tank ,filledwith water of densityrhoas showninthe figure. The heightof the baseof cylinderfrom the baseof tankis H . Let the cylinder is prevented frommovingup , by applying a force and water level is furtherdecreased . Then , height of water level(h_(2) in figure ) for which the cylinder remains in originalposition withoutapplicationof force is
Answer» h/3 4h/9 2h/3 h Answer :B

Discussion

4772.	A ray of light is incident at 60^@, refracting angle of the prism being 30^@ . The ray imerging out of the prism makes an angle of 30^@ with the incident ray. If the imergent ray is perpendicular to the face it immerges, what is the RI of the material of the prism?
Answer» 1.5 1.6 `SQRT3` `SQRT2` ANSWER :C

Discussion

4773.	Two point charges q_1 and q_2 are fixed at a separation of 20 cm. Locate the point(s) on the line joining the charges where the net electric field intensity is zero. (i)q_1=+2muC and q_2=-4 muC (ii)q_1=+2muC and q_2=-2muC (iii)q_1=+2muC and q_2=+4muC
Answer» SOLUTION :(i) `(1+sqrt2)/5` m to the left of `q_1` , (ii) no such point EXIST , (III) `(sqrt2-1)/5` m to the right of `q_1`

Discussion

4774.	A hollow charged conductor has a tiny hole cut into its surface. Show that the electric field in the hole is((sigma )/(2in_0))hatn, where hatnis the unit vector in the outward normal direction, andsigmais the surface charge density near the hole,
Answer» Solution :Let us consider a hollow charged conducting BODY, P having a tiny hole H cut into its surface, If `sigma ` be the surface density of charge near the hole , then we know that the electricfield at a point B outside the conductor and near the hole =`oversetto E= (sigma )/(in_0)hatn, ` and electric field at a point A inside the hollow conductor =0. Obviously electric field at point A as well as B may be considered as the VECTOR sum of electric field due to the ramaining conductor `oversetto (E_1)`and electric field due to hole portion of the conductor ` oversetto (E_2) ` As shown in at point A, we have ` \|oversetto(E)\| =\|oversetto (E_1)+ oversetto(E_2)\| =oversetto(E_1)-oversetto(E_2)=0 and ` it leads to ` \|oversetto(E_1) = \|oversetto(E_2)\|` Again at point B, `\|oversetto(E_1)=\|oversetto(E_1) +oversetto(E_2) \| =oversettoE_1+oversetto(E_2)=2 E_1 =(sigma )/(in_0) ` ` rArr ""oversetto(E_1) = ( sigma )/( 2in _0) hatn , `where `hatn `is unit vector in the outwordnormal direction. ` (##U_LIK_SP_PHY_XII_C01_E02_005_S01.png" width="80%">

Discussion

4775.	Two plane mirrors are inclined at 70^@. A ray incident on one mirror at angle theta . after reflection falls on the second mirror and after reflected from there it moves parallel to the first mirror. Then thetais:
Answer» `50^@` `45^@` `30^@` `55^@` ANSWER :A

Discussion

4776.	n type and p type semiconductors can be obtained by doping pure silicon respectively with
Answer» ARSENIC, PHOSPHORUS indium aluminium phosphorus, indium aluminium boron Solution :PHOSPHOURS is PENTAVALENT, Indium is trivalent .

Discussion

4777.	Hysteresisis exhibited by a ……….. . Substance.
Answer» parmagnetic FERROMAGNETIC diamagentic All of these Answer :B

Discussion

4778.	A parallel beam is incident on a convex lens of focal length f. It is then put in correct with a concave lens of focal length (f)/(2). What will happen to image?
Answer» REAL at `V = (F)/(2)` real at v = f VIRTUAL at `v = (f)/(2)` virtual at v = f. Answer :A

Discussion

4779.	X,Y and Z are parallel plates. Y is given some positive charge. Two electrons A and B start form X and Z respectively and reach Y in times t_(A) and t_(B) respectively.
Answer» `t_(A)=t_(B)` `t_(A)=SQRT(2)t_(B)` `2t_(A)=t_(B)` `t_(A)=2t_(B)` ANSWER :D

Discussion

4780.	What are coherent sources? Why are coherent sources required toproduce interference of light? Give an example of interference of light in everyday life. In Young's double-slit experiment, the two slits are 0.03 cm apart and the screen is placed at a distance of 1.5 m away from the slits. The distance between the central bright fringe and fourth bright fringe is 1 cm. Calculate the wavelength of light used.
Answer» SOLUTION :`d = 0.03 cm = 0.03 xx 10^(-2)m` `D = 1.5 m` `B_4 = (4 LAMBDA D)/(d) = 1 xx 10^(-2) m` `lambda = (1 xx 10^(-2)d)/(4D)` `=(10^(-2) xx 0.03 xx 10^(-2))/(4 xx 1.5)` `= 0.005 xx 10^(-4) m`.

Discussion

4781.	The 6563 A^(0) line emittedby hudrogenatom is a star is foundto be red shiftedby 5A^(0).the speed with whichthe staris recedingfrom the earth is
Answer» `17.3 xx10^(3)`m/s `4.29 xx10^(7)` m/s `3.39 xx10^(5)` m/s `2.29 xx10^(5)` m/s ANSWER :D

Discussion

4782.	Which of the following functions represent a travelling wave
Answer» `(x-VT)^2` `(x + vt)^2` `E^(-(x-vt)^2)` `(1)/(x + vt)` Answer :C

Discussion

4783.	When two vectors vecA and vecB of magnitudes *a' and 'b' respectively are added, the magnitude of resultant vector is always
Answer» EQUAL to (a + B) LESS than (a + b) GREATER than (a + b) Not greater than (a + b) ANSWER :D

Discussion

4784.	A beam of light consisting of two wavelengths, 650 nm and 520 nm, is used to obtain interference fringes in a Young's double-slit experiment. (a) Find the distance of the third bright fringe on the screen, from the central maximum for wavelength 650 nm. (b) What is the least distance from the central maximum where the bright fringes due to both the wavelength coincide ?
Answer» Solution :Here `lamda_(1)=650nm=6.5xx10^(-7)m,lamda_(2)=520nm=5.2xx10^(-7)m,d=1mm=10^(-3)m,D=60cm=0.6m` (a) Distance of third bright fringe from the central bright fringe for wavelength `lamda_(1)=650nm` `x_(3)=(3Dlamda)/(2)=(3xx0.6xx6.5xx10^(-7))/(1xx10^(-3))=1.17xx10^(-3)m=1.17mm` (b) Let at a distance x from central MAXIMA the bright fringes due to wavelength `lamda_(1) and lamda_(2)` coincide first time. for this to happen, `nlamda_(1)=(n+1)lamda_(2)`, where n is an integer `IMPLIES(n+1)/(n)=(lamda_(1))/(lamda_(2))=(6.5xx10^(-7))/(5.2xx10^(-7)m)=(5)/(4)impliesn=4` It means that at distance nth (4th) maxima for wavelength `lamda_(1)` is just coinciding with (n+1)st (5TH) maxima for wavelength `lamda_(2)` `therefore=x=(nDlamda_(1))/(d)=(4xx0.6xx6.5xx10^(-7))/(1xx10^(3))=1.56xx10^(-3) m=1.56mm`.

Discussion

4785.	The work function of a substance is 4eV. The longest wavelength of light that can cause photoelectron emission from this substance is approximately
Answer» 310 nm 400 nm 540 nm 220 nm Answer :A

Discussion

4786.	Fill in the blanks with appropriate words given below . [Base , collector , emitter , base-collector junction, collector - emitter junction , emitter base junction ] Structurally a bipolar junction transistor consists of emitter , base and underline"(i)" Out of these regions underline"(ii)"is the most heavily doped. For proper functioning of a transistor. underline"(iii)"is forward biased and underline"(iv)"is reverse biased.
Answer» SOLUTION :i. Collectorii., emitteriii E-B junctioniv. C-B JUNCTION

Discussion

4787.	The time period of a particle in simple harmonic motion is 8 second. At t = 0 it is at the mean position. The ratio of the distances travelled by it in the first and second is :
Answer» `1//2` `1//(sqrt(2)-1)` `1//sqrt(2)` `1//sqrt(3)`. Solution :`y=R sin omega t` `:. Y_(1)=r sin omega xx 1` and `y_(2)=r sin omega xx2`. `:.""(y_(1))/(y_(2))=(sinomega)/(sin 2omega)=(1)/(2 cos omega)=(1)/(2.cos""(2PI)/(T))=(1)/(2 cos((2pi)/(8)))` `:.""(y_(1))/(y_(2))=(1)/(sqrt(2)):.y_(2)=sqrt(2)y_(1)` `:.` Distance coveredin `2"nd"=y_(2)-y_(1)=sqrt(2)y_(1)-y_(1)` `=(sqrt(2)-1)y_(1)` `:.` ratio of distances covered in Ist SECOND and 2ND second `=(1)/(sqrt(2)-1)` Correctchoiceis (b).

Discussion

4788.	The ratio of the surface area of the nuclei ""_(52)Te^(125) to that of ""_(13)Al^(27) is
Answer» (a)`5/3` (B)`125/17` (C)`1/4` (d)`25/9` ANSWER :D

Discussion

4789.	A If the wavelength of the incident radiation changes from lamda_(1) to lamda_(2) then the maximum kinetic energy of the emitted photo electrons changes from K to K,, then the work function of the emitter surface is
Answer» `(lamda_(1)K_(1)-lamda_(2)K_(2))/(lamda_(2)-lamda_(1))` `(lamda_(1)K_(2)-lamda_(2)K_(1))/(lamda_(1)-lamda_(2))` `(K_(2)-K_(1))/(lamda_(1)K_(1)-lamda_(2)K_(2))` `(lamda_(2)-lamda_(1))/(lamda_(2)K_(1)-lamda_(1)K_(2))` ANSWER :A

Discussion

4790.	Submarine rescue. When the U.S. submarine Squalus became disabled at a depth of 80 m, a cylindrical chamber was lowered from a ship to rescue the crew. The chamber had a radius of 1.00 m and a height of 3.50 m, was open at the bottom, and held two rescuers. It slid along a guide cable that a diver had attached to a hatch on the submarine. Once the chamber reached the hatch and clamped to the hull, the crew could escape into the chamber. During the descent, air was released from tanks to prevent water from flooding the chamber. Assume that the interior air pressure matched the water pressure at depth h as given by P_0+ rho gh, where P_0= 1.000 atm is the surface pressure and p= 1024 kg/m^3 is the density of seawater. Assume a surface temperature of 20.0°C and a submerged water temperature of -40.0^@ C. (a) What is the air volume in the chamber at the surface? (b) If air had not been released from the tanks, what would have been the air volume in the chamber at depth h = 80.0 m? (c) How many moles of air were needed to be released to maintain the original air volume in the chamber?
Answer» SOLUTION :`10.996m^3~~ 11.0 m^3, (B )4.40 XX 10^3 J (C )4.68 xx 10^3mol`

Discussion

4791.	Calculate Osmotic Pressure of a solution obtained on mixing 100 mL of 3.4%(wt/vol) "solution of area" (Mol.wt 60) "and" 50 mL "of" 1.6%(wt//vol) "solution of canesugar" (Mol.Wt 342) "at" 27^(@)
Answer» 9.704 10 12.74 15 Answer :1

Discussion

4792.	In a game of lawn chess, where pieces are moved between the centers of squares that are each 1.00 m on edge, a knight is moved in the following way: (1) two squares forward, one square rightward, (2) two squares leftward, one square forward, (3) two squares forward, one square leftward. What are (a) the magnitude and (b) the angle (relative to "forward") of the knight's overall displacement for the series of three moves ?
Answer» SOLUTION :`5.39 m at 21.8` LEFT of FORWARD

Discussion

4793.	A magnetic pole of strength 4 Am is moved twice around a long straight wire carrying a current of 3A. The work done is
Answer» `96pixx10^(-7)J` `48pixx10^(-7)J` `108pixx10^(-7)J` zero Answer :A

Discussion

4794.	Which of the following device acts a complete electronic circuit?
Answer» Junction DIODE Integrated circuit Junction transistor ZENER diode SOLUTION : Integrated circuit Integrated circuit is a complete circuit of the electronics circuit.

Discussion

4795.	Domain formatiuon is necessary feature of :
Answer» Non-magnetics Diamagnetics Paramagnetic Ferromagnetics Answer :D

Discussion

4796.	When the electric flux linked with the surface will be positive.
Answer» `THETA gt 90^(@)` `theta LT 90^(@)` `theta = 90^(@)` `theta GE 90^(@)` SOLUTION :[`phi=Abcostheta` and for `theta lt 90^(@) costheta` positive]

Discussion

4797.	STATEMENT -1 : A small object if released from rest from a point upon the axis of a large mass circular ring, but very near to the centre of ring, will perform SHM. and STATEMENT -2 : The gravitational field of mass circular ring changes non-linearly with the axial distance, near the centre.
Answer» STATEMENT 1- True, Statement -2 is True, Statement -2 is a correct EXPLANATION for Statement -1 Statement -1 is True, Statement -2 is True, Statement -2 is NOT a correct explanation for Statement -1 Statement -1 is True, Statement -2 is False Statement -1 is False, Statement -2 is True Answer :C

Discussion

4798.	Let E_(0) and B_(0) denote the amplitude of electric and magnetic filed of a plane electromagnetic wave in air. The magnitude of the average momentum transferred per unit area and per unit time to a totally abosorbing surface is
Answer» `1/2 epsi _(0) E_(0) ^(2)` `1/2 mu_(0) B_(0)` `epsi _(0) E_(0) ^(2)` `(B_(0) ^(2))/(mu_(0))` Solution :Intensity of electromagnetic wave, `I = 1/2 epsi _(0) E_(0) ^(2)c =(1 B_(0) ^(2) c)/(mu_(0))` where `E_(0)=` electric field and c = speed of LIGHT. Now, momentum transfer per unit area per unit time, which is also called radiation PRESSURE. `I/A ((Deltap )/(DELTA t)) = I /c = ((1)/(2)epsi _(0) E_(0)^(2)c)/(c )` `I /c =1/2 epsi _(0) E_(0)^(2)` [where, `Deltap,=` momentum transferred, `DELTAT=` time and A = area.]

Discussion

4799.	Consider a coin of Question 20. It is electrically neutral and contains equal amounts of positive and negative charge of magnitude 34.8 kC. Suppose that these equal charges were concentrated in two point charges separated by: (i) 1 cm (-1/2) xx displacement of the one paisa coin) (ii) 100 m (-length of a long building) (iii) 10^(6) m (radius of the earth). Find the force on each such point charge in each of the three cases. What do you conclude from these results ?
Answer» Solution :Here, `r_(1) = 1 cm = 10^(-2)` m `r_(2) = 100 m` `r_(3) = 10^(6) m` `1/(4pi epsilon_(0)) = k = 9 xx 10^(9)` (i) `F_(1) = (k\|q\|^(2))/(r_(1)^(2)) =(9 xx 10^(9) xx (3.48 xx 10^(4))^(2))/(10^(-2))^(2)` `=1.09 xx 10^(23)` N (ii) `F_(2) = (k\|q\|^(2))/r_(2)^(2) = (9 xx 10^(9) xx (3.48 xx 10^(4))^(2))/(100)^(2) = 1.09 xx 10^(15)` N (iii) `F_(3) = (k\|q\|^(2))/r_(3)^(2) = (9 xx 10^(9) xx (3.48 xx 10^(4))^(2))/(10^(6))^(2)` `=1.09 xx 10^(7)` N Conclusion : Here, the force between charges is MUCH more hence, it is difficult to disturb electrical neutrality of matter.

Discussion

4800.	A beam of light of wavelength 600 nm from a distant source falls on a single slit 1.00 mm wide and the resulting diffraction pattern is observed on a scfeen 2 m away.The distance between the first dark fringes on either side of the central bright fringe is :
Answer» `1.2 CM` `1.2 mm` `2.4 cm` `2.4 mm` Solution :`d SIN THETA = n LAMBDA` `sin theta approx thetaapprox (y)/(D)` So position of first MINIMA is `d.(y)/(D) = lambda` `y = (D)/(d) lambda = 1.2` mm

Discussion

Explore topic-wise InterviewSolutions in .

In an AC circuit the applied potential difference and the current flowing are given by : V = 200 sin 100 t volt, I= 5sin(100t +(pi)/(2))amp The power consumption is equal to :

Up to what temperature has one to heat classiacal electronic gas to make the mean enrgy of its electrons equal to that of free electrons in copper at T=0? Only one free electron is supposed to correspond to each other atom.

An alpha particle, a proton and an electron are moving with equal kinetic energy. Which one of these particles has the longest de Broglie wavelength? Give reason.

Assertion In Young's double slit experiment, often both the phenomena interference and diffraction are present Reason Diffraction results due to superposition of wavelets from different points of the some wavefront

All components of the electromagnetic spectrum in vaccum have the same

11xx10^(11) photons are incident on a surface in 100s.These photons correspond to a wavelength of 10Å .If the surface area of the given surface is 0.01 m^(2) ,the intensity of given radiations is ………(velocity of light is 3xx10^(8)ms^(-1),h=6.625x10^(-34)JS)

How can you calculate the amount of heat received (or delivered) by a system, using the T-S diagram?

For a given photosensitive material and with a source of constant frequency of incident radiation, how does the photocurrent vary with the intensity of incident light ?

In a metere bridge, the balance length from left end (standard resistance of 1 Omegais in theright gap) is found to be 20cm the length of resistance in left gap is 1/2 m and radius is 2mm its specific resistance is

The centripetal acceleration of an electron in a Bohr's orbit is proportional to:

Assertion: Standard optical diffraction can not beusedfordiscriminating between different X-rays wavelength. Reason: The grating spacing is not of the order of X-rays wavelengths.

In the circuit shown in figure, if the diode forward voltage drop is 0.3 V, the voltage difference between A and B is

White light is used to illuminate two slits in a YDSE. The separation between the slits is d and the screen is at a distance D(D gt gt d) from the slits. At a point on the screen direcrtly in front of one of the slits, which of the following wavelengths are missing.

You are given two concave mirrors of different aperture sizes. Which one of the two you may select to get a sharper image?

In satellite communication 1. The frequency used lies between 5 MHz and 10 MHz. 2.The uplink and downlink frequencies are different. 3. The orbit of geostationary satellite lies in the equatorial plane at an inclination of 0^(@)

Resolving power of an optical instrument is associated with :

According to the author what was garbage for the parents?

Ratio of intensities of two waves are given by 4:1. Then ratio of the amplitudes of the two waves is

If vec A =2 hat i+ 3 hat j+ 8 hat k is perpendicular to vec B= 4 hat j -4 hat i+ alpha hat k, then the value of alpha

A long current carrying wire, carrying current such that it is flowing out from the plane of paper, is placed at O. A steady state current is flowing in the loop ABCD. Then,

A ray of light is incident at 60^@, refracting angle of the prism being 30^@ . The ray imerging out of the prism makes an angle of 30^@ with the incident ray. If the imergent ray is perpendicular to the face it immerges, what is the RI of the material of the prism?

Two point charges q_1 and q_2 are fixed at a separation of 20 cm. Locate the point(s) on the line joining the charges where the net electric field intensity is zero. (i)q_1=+2muC and q_2=-4 muC (ii)q_1=+2muC and q_2=-2muC (iii)q_1=+2muC and q_2=+4muC

A hollow charged conductor has a tiny hole cut into its surface. Show that the electric field in the hole is((sigma )/(2in_0))hatn, where hatnis the unit vector in the outward normal direction, andsigmais the surface charge density near the hole,

Two plane mirrors are inclined at 70^@. A ray incident on one mirror at angle theta . after reflection falls on the second mirror and after reflected from there it moves parallel to the first mirror. Then thetais:

n type and p type semiconductors can be obtained by doping pure silicon respectively with

Hysteresisis exhibited by a ……….. . Substance.

A parallel beam is incident on a convex lens of focal length f. It is then put in correct with a concave lens of focal length (f)/(2). What will happen to image?

X,Y and Z are parallel plates. Y is given some positive charge. Two electrons A and B start form X and Z respectively and reach Y in times t_(A) and t_(B) respectively.

The 6563 A^(0) line emittedby hudrogenatom is a star is foundto be red shiftedby 5A^(0).the speed with whichthe staris recedingfrom the earth is

Which of the following functions represent a travelling wave

When two vectors vecA and vecB of magnitudes *a' and 'b' respectively are added, the magnitude of resultant vector is always

The work function of a substance is 4eV. The longest wavelength of light that can cause photoelectron emission from this substance is approximately

The time period of a particle in simple harmonic motion is 8 second. At t = 0 it is at the mean position. The ratio of the distances travelled by it in the first and second is :

The ratio of the surface area of the nuclei ""_(52)Te^(125) to that of ""_(13)Al^(27) is

A If the wavelength of the incident radiation changes from lamda_(1) to lamda_(2) then the maximum kinetic energy of the emitted photo electrons changes from K to K,, then the work function of the emitter surface is

Calculate Osmotic Pressure of a solution obtained on mixing 100 mL of 3.4%(wt/vol) "solution of area" (Mol.wt 60) "and" 50 mL "of" 1.6%(wt//vol) "solution of canesugar" (Mol.Wt 342) "at" 27^(@)

A magnetic pole of strength 4 Am is moved twice around a long straight wire carrying a current of 3A. The work done is

Which of the following device acts a complete electronic circuit?

Domain formatiuon is necessary feature of :

When the electric flux linked with the surface will be positive.

STATEMENT -1 : A small object if released from rest from a point upon the axis of a large mass circular ring, but very near to the centre of ring, will perform SHM. and STATEMENT -2 : The gravitational field of mass circular ring changes non-linearly with the axial distance, near the centre.

Let E_(0) and B_(0) denote the amplitude of electric and magnetic filed of a plane electromagnetic wave in air. The magnitude of the average momentum transferred per unit area and per unit time to a totally abosorbing surface is

A beam of light of wavelength 600 nm from a distant source falls on a single slit 1.00 mm wide and the resulting diffraction pattern is observed on a scfeen 2 m away.The distance between the first dark fringes on either side of the central bright fringe is :