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.

45301.

Carbon, silicon and germanium have four valence electrons each. These are characterised by valence and conduction bands separated by energy band gap respectively equal to (E_g)_c, (E_g)_(Si) and (E_g)_(Ge) Which of the following statements is true?

Answer» <html><body><p>`E_g)_(<a href="https://interviewquestions.tuteehub.com/tag/si-630826" style="font-weight:bold;" target="_blank" title="Click to know more about SI">SI</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>(E_g)_(Ge)lt(E_g)_c`<br/>`(E_g)_clt (E_g)_(Si) lt (E_g)_(Ge)`<br/>`(E_g)_clt (E_g)_(Si)gt (E_g)_(Ge)`<br/>`(E_g)_clt (E_g)_(Si) = (E_g)_(Ge)`</p>Answer :C</body></html>
Discussion
45302.

A: Short wave bands are used for transmission of radio waves to a large distance. R: Short waves are reflected by ionosphere.

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>
Discussion
45303.

The heat generated in a circuit is given by Q=I^(2)Rt, where I is current, R is resistance and t is time. If the percentage errors in measuring I,R and t are 2%,1% and 1% respectively, then the maximum error in measuring heat will be :

Answer» <html><body><p>`2%`<br/>`<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/>`4%`<br/>`6%`</p>Solution :Here `Q=I^(2)Rt` <br/> `:.(dQ)/(Q)<a href="https://interviewquestions.tuteehub.com/tag/xx100-3292680" style="font-weight:bold;" target="_blank" title="Click to know more about XX100">XX100</a>=2(<a href="https://interviewquestions.tuteehub.com/tag/di-431875" style="font-weight:bold;" target="_blank" title="Click to know more about DI">DI</a>)/(I)xx100+(dR)/(R)xx100+(<a href="https://interviewquestions.tuteehub.com/tag/dt-960413" style="font-weight:bold;" target="_blank" title="Click to know more about DT">DT</a>)/(t)xx100` <br/> `2xx2%+1%+1%` <br/> <a href="https://interviewquestions.tuteehub.com/tag/hence-484344" style="font-weight:bold;" target="_blank" title="Click to know more about HENCE">HENCE</a> `(d)` is correct.</body></html>
Discussion
45304.

In Bohr model of hydrogen atom, which of the following is quantised?

Answer» <html><body><p><a href="https://interviewquestions.tuteehub.com/tag/linear-1074458" style="font-weight:bold;" target="_blank" title="Click to know more about LINEAR">LINEAR</a> <a href="https://interviewquestions.tuteehub.com/tag/velocity-1444512" style="font-weight:bold;" target="_blank" title="Click to know more about VELOCITY">VELOCITY</a> of electron<br/>angular <a href="https://interviewquestions.tuteehub.com/tag/veocity-2323014" style="font-weight:bold;" target="_blank" title="Click to know more about VEOCITY">VEOCITY</a> of electron<br/>linear <a href="https://interviewquestions.tuteehub.com/tag/momentum-1100588" style="font-weight:bold;" target="_blank" title="Click to know more about MOMENTUM">MOMENTUM</a> of electron<br/>angular momentum of electron</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
45305.

We are given the job of designing a large horizontal ring that will rotate around a vertical axis and that will have a radius of r = 33.1 m. Passengers will enter through a door in the outer wall of the ring and then stand next to that wall. We decide that for the time interval t = 0 to t = 2.30 s, the angular position theta(t) of a reference line on the ring will be given by theta=ct^(3), with c=6.39xx10^(-2)rad//s^(3). After t = 2.30 s, the angular speed will be held constant until the end of the ride. Once the ring begins to rotate, the floor of the ring will drop away from the riders but the riders will not fall - indeed, they feel as though they are pinned to the wall. For the time t = 2.20 s, let's determine a rider's angular speed omega, linear speed nu, angular acceleration alpha, tangential acceleration a_(t), radial acceleration a_(r), and acceleration veca.

Answer» <html><body><p></p>Solution :(1) The angular speed `omega` is given by Eq. `(omega=d theta//dt)`. (2) The linear speed `nu` (along the circular path) is related to the angular speed (<a href="https://interviewquestions.tuteehub.com/tag/around-5602275" style="font-weight:bold;" target="_blank" title="Click to know more about AROUND">AROUND</a> the rotation axis) by Eq. `(nu=omegar)`. (3) The angular acceleration `alpha` is given by Eq. `(alpha=domega//dt)`. (4) The tangential acceleration `a_(t)` (along the circular path) is related to the angular acceleration (around the rotation axis) by Eq. `(a_(t)=alphar)`. (5) The radial acceleration `a_(r)` is given Eq. `(a_(r)=omega^(2)r)`. (6) The tangential and radial accelerations are the (perpendicular) components of the (full) acceleration `veca`. <br/> Calculations: Let.s go through the steps. We first find the angular velocity by taking the time derivative of the given angular position function and then substituting the given time of t = 2.20 s: <br/> `omega=(d theta)/(dt)=d/dt(ct^(3))=3ct^(2)` <br/> = `3(6.39xx10^(-2)rad//s^(3))(2.20s)^(2)` <br/> = 0.928 rad/s. <br/> the linear speed just then is <br/> `nu=omegar=3ct^(2)r` <br/> = `3(6.39xx10^(-2)rad//s^(3))(2.20s)^(2)(33.1m)` <br/> = 30.7 m/s. <br/> Next, let.s tackle the angular acceleration by taking the time derivative of Eq. <br/> `alpha=(domega)/(dt)=d/dt(3ct^(2))=6ct` <br/> = `6(6.39xx10^(-2)rad//s^(3))(2.20s)=0.843rad//s^(2)`. <br/> The tangential acceleration then follows from Eq. <br/> `a_(1)=alphar=6ctr` <br/> = `6(6.30xx10^(-2)rad//s^(3))(2.20s)^(2)(33.1m)` <br/> = `27.91m//s^(2)~~27.9m//s^(2)`. <br/> or 2.8 g Eq. tells us that the tangential acceleration is increasing with time (but it will cut off at t = 2.30 s). From Eq, we write the radial acceleration as <br/> `a_(r)=omega^(2)r`. <br/> Substituting from Eq. leads us to <br/> `a_(r)=(3ct^(2))^(2)r=<a href="https://interviewquestions.tuteehub.com/tag/9c-343131" style="font-weight:bold;" target="_blank" title="Click to know more about 9C">9C</a>^(2)t^(4)r` <br/> = `9(6.39xx10^(-2)rad//s^(3))^(2)(2.20s)^(4)(33.1m)` <br/> = `28.49m//s^(2)~~28.5m//s^(2)`, <br/> or 2.9 g (which is <a href="https://interviewquestions.tuteehub.com/tag/also-373387" style="font-weight:bold;" target="_blank" title="Click to know more about ALSO">ALSO</a> reasonable and a bit <a href="https://interviewquestions.tuteehub.com/tag/exciting-2625861" style="font-weight:bold;" target="_blank" title="Click to know more about EXCITING">EXCITING</a>). <br/> The radial and tangential accelerations are perpendicular to each other and form the components of the rider.s acceleration `veca`. The magnitude of `veca` is given by <br/> `a=sqrt(a_(r)^(2)+a_(t)^(2))` <br/> = `sqrt((28.49m//s^(2))^(2)+(27.91m//s^(2))^(2))` <br/> `~~39.9m//s^(2)`. <br/> or 4.1 g (which is really exciting). All these values are acceptable. <br/> To find the orientation of `veca`, we can calculate the angle `theta` <a href="https://interviewquestions.tuteehub.com/tag/shown-1206565" style="font-weight:bold;" target="_blank" title="Click to know more about SHOWN">SHOWN</a> in Fig. <br/> `tantheta=a_(t)/a_(r)`. <br/> However, instead of substituting our numerical results, let.s use the algebraic results from Eq. <br/> `theta=tan^(-1)((6ctr)/(9c^(2)t^(4)r))=tan^(-1)(2/(3ct^(3)))`. <br/> The big advantage of solving for the angle algebraically is that we can then see that the angle (1) does not depend on the ring.s radius and (2) decreases as t goes from 0 to 2.20 s. That is, the acceleration vector `veca` swings toward being radially inward because the radial acceleration (which depends on `t^(4)`) quickly dominates over the tangential acceleration (which depends on only t). At our given time t = 2.20 s, we have <br/> `theta="tan"^(-1)2/(3(6.39xx10^(-2)rad//s^(3))(2.20s)^(3))=44.4^(@)`.</body></html>
Discussion
45306.

Obtain the equation of thin lens.

Answer» <html><body><p></p>Solution :For refraction at two spherical surfaces of lens,<br/>`(n_1)/(-u)+(n_1)/(v)=(n_2-n_1)[(<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>)/(R_1)-(1)/(R_2)]`<br/>`therefore(1)/(-u)+(1)/(v)=((n_2)/(n_1)-1)[(1)/(R_1)-(1)/(R_2)]` [`therefore` <a href="https://interviewquestions.tuteehub.com/tag/dividing-957391" style="font-weight:bold;" target="_blank" title="Click to know more about DIVIDING">DIVIDING</a> by `n_1`]<br/>`therefore(1)/(-u)+(1)/(v)=(n_(21)-1)[(1)/(R_1)-(1)/(R_2)]` ... (1)<br/>and lens maker.s formula,<br/>`1/f=(n_(21)-1)[(1)/(R_1)-(1)/(R_2)]` ... (2)<br/>By comparing equation (1) and (2),<br/>`1/f=(1)/(-u)+(1)/(v)` or `1/f=1/v-1/u`<br/>Here, the <a href="https://interviewquestions.tuteehub.com/tag/distances-956488" style="font-weight:bold;" target="_blank" title="Click to know more about DISTANCES">DISTANCES</a> are as per sign conventior and this equation is true for real and virtua images of convex and concave lenses.</body></html>
Discussion
45307.

Prove that the total current which is the sum of conduction current and displacement current is always continuous and any loss in conduction current (I_C) appears as displacement current (I_D).

Answer» <html><body><p></p>Solution :Consider a volume V in a medium through which <br/> currents are flowing. Let `I_c` be the conduction <br/> current entering the volume V and `I_c'` be the <br/> conduction current leaving the volume V. Then <br/> total charges entering and leaving the volume in <br/> time dt will be `I_c` and `I_c'`dt. Therefore, the <br/> <a href="https://interviewquestions.tuteehub.com/tag/charge-914384" style="font-weight:bold;" target="_blank" title="Click to know more about CHARGE">CHARGE</a> <a href="https://interviewquestions.tuteehub.com/tag/accumulated-366703" style="font-weight:bold;" target="_blank" title="Click to know more about ACCUMULATED">ACCUMULATED</a> inside the volume V during <br/> time dt is <a href="https://interviewquestions.tuteehub.com/tag/given-473447" style="font-weight:bold;" target="_blank" title="Click to know more about GIVEN">GIVEN</a> by dq(inside V)=`I_cdt-I_c'dt` <br/> or `(dq)/(dt)=I_c-I_c'....(i)` <br/> From Gauss's Theoram in electrostatics, we have <br/> `phi_E=ointvecE.vec(<a href="https://interviewquestions.tuteehub.com/tag/ds-960390" style="font-weight:bold;" target="_blank" title="Click to know more about DS">DS</a>)=q/(in_0) ("inside") or in_0 phi_E=q` <br/> or `I_d=in_0 (dphi_E)/(dt)=(d (in_0phi_E))/(dt)=(dq)/(dt) ......(ii)` <br/> From (i) and (ii), <br/> `I_c-I_c'=I_d or I_c=I_d+I_c'` <br/> Thus we conclude that the loss of conduction <br/> current `(=I_c-I_c')` appears as the <a href="https://interviewquestions.tuteehub.com/tag/displacement-956081" style="font-weight:bold;" target="_blank" title="Click to know more about DISPLACEMENT">DISPLACEMENT</a> <br/> current `(I_d)` and conduction current plus <br/> displacement current remains constant i.e., <br/> `I_c'+I_d`= a constant.</body></html>
Discussion
45308.

The focal length of a convex lens is 10 cm. Find its magnifying power when it is used as a magnifying glass to form the image at (i) near point and (ii) far point.

Answer» <html><body><p>3.5, 2.5<br/>2.5, 3.5 <br/>2.5, 1.5<br/>1.5, 2.5 </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>
Discussion
45309.

The focal length of the objective and of the eye- piece of compound microscope are f_(0) and f_(e) respectively. If L is the tube length and d, the least distance of distinct vision, then its angular magnification, when the image is formed at infinity, is

Answer» <html><body><p>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> - (<a href="https://interviewquestions.tuteehub.com/tag/l-535906" style="font-weight:bold;" target="_blank" title="Click to know more about L">L</a>)/(f_(<a href="https://interviewquestions.tuteehub.com/tag/0-251616" style="font-weight:bold;" target="_blank" title="Click to know more about 0">0</a>)) ) ((D)/(f_(e)))` <br/>b. `(1 + (L)/(f_(0)) ) ((D)/(f_(e)))` <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>. `(L)/(f_(0))(1 - (D)/(f_(0)) ) ` <br/>d. `(L)/(f_(0))((D)/(f_(e)) ) ` </p></body></html>
Discussion
45310.

The resistanceof a rectangular blockof copperof dimension2 mm xx2 mm xx 5 m betweentwosquarefacesis 0.02 Omega . Whatist he resistivity ofcopper ?

Answer» <html><body><p>`1.<a href="https://interviewquestions.tuteehub.com/tag/6-327005" style="font-weight:bold;" target="_blank" title="Click to know more about 6">6</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> 10^(-6) <a href="https://interviewquestions.tuteehub.com/tag/omega-585625" style="font-weight:bold;" target="_blank" title="Click to know more about OMEGA">OMEGA</a>`<br/>`1.6 xx 10^(-6) Omega-m`<br/>`1.6 xx 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>) Omega -m`<br/>Zero</p>Answer :C</body></html>
Discussion
45311.

The X-ray beam coming from an X-ray tube will be

Answer» <html><body><p>monochromatic <br/>having all wavelengths smaller than a <a href="https://interviewquestions.tuteehub.com/tag/certain-407894" style="font-weight:bold;" target="_blank" title="Click to know more about CERTAIN">CERTAIN</a> maximum <a href="https://interviewquestions.tuteehub.com/tag/wavelength-1450414" style="font-weight:bold;" target="_blank" title="Click to know more about WAVELENGTH">WAVELENGTH</a> <br/>having all the wavelengths <a href="https://interviewquestions.tuteehub.com/tag/larger-1067345" style="font-weight:bold;" target="_blank" title="Click to know more about LARGER">LARGER</a> than a certain <a href="https://interviewquestions.tuteehub.com/tag/minimum-561095" style="font-weight:bold;" target="_blank" title="Click to know more about MINIMUM">MINIMUM</a> wavelength<br/>having all wavelengths lying between a minimum and a maximum wave length</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
45312.

An inductance of 1 mH, a condenser of 10 muF and a resistance of 50 Omega are connected in series. The reactances of inductors and condensers are same. What will be the reactance of either of them ?

Answer» <html><body><p>`5 Omega`<br/>`3 Omega`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/7omega-1921559" style="font-weight:bold;" target="_blank" title="Click to know more about 7OMEGA">7OMEGA</a>`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/10-261113" style="font-weight:bold;" target="_blank" title="Click to know more about 10">10</a> Omega`</p>Solution :Here L=1mH = `1xx10^(-3)` H <br/>`C=10 muF =10xx10^(-6)`F <br/> `R=50 Omega "" <a href="https://interviewquestions.tuteehub.com/tag/therefore-706901" style="font-weight:bold;" target="_blank" title="Click to know more about THEREFORE">THEREFORE</a>=10^4` rad/s <br/> `X_L=X_C` and `X_L=omegaL` <br/> `=10^4 <a href="https://interviewquestions.tuteehub.com/tag/xx-747671" style="font-weight:bold;" target="_blank" title="Click to know more about XX">XX</a> 1xx10^(-3)` <br/>`omegaL=1/(omegaC)` <br/>`therefore X_L=10Omega` <br/> `therefore omega^2=1/(<a href="https://interviewquestions.tuteehub.com/tag/lc-536651" style="font-weight:bold;" target="_blank" title="Click to know more about LC">LC</a>) "" X_C=1/(OmegaC)` <br/> `=1/(1xx10^(-3)xx10xx10^(-6)) "" 1/(10^4xx10xx10^(-6))` <br/> `=10^8` <br/> `therefore X_C=10 Omega`</body></html>
Discussion
45313.

About 5% of the power of a 100 W light bulb is converted to visible radiation . What is the average intensity of visible radiationat a distance of 1 m from the bulb ? Assume that the radiation is emitted isotropically and neglect reflection .

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) `0.4 W//m^(<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/> (<a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a>) `0.004 W//m^(2)`</body></html>
Discussion
45314.

The magnetic field is…………………….around a conductor in which its magnetic effect can be felt.

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 <a href="https://interviewquestions.tuteehub.com/tag/space-649515" style="font-weight:bold;" target="_blank" title="Click to know more about SPACE">SPACE</a></body></html>
Discussion
45315.

One gram mole of nitrogen at 27^(@)C and 1 atm pressure is contained in a vessel and the molecules are moving with their speed. The number of collisions per second which the molecules make with an area of 1m^(2) on the vessel's wall is

Answer» <html><body><p>`2xx10^(27)` <br/>`2xx10^(20)`<br/>`2xx10^(10)`<br/>`2xx10^(<a href="https://interviewquestions.tuteehub.com/tag/24-295400" style="font-weight:bold;" target="_blank" title="Click to know more about 24">24</a>)`</p>Solution :Number of collisions can be calculated as `n(2mv_(rms))=PA` <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> n=[(PA)/(2mv_(rms))],"where "v_(rms)=[(3RT)/(M)]^(1//2)` <br/> `v_(rms)=sqrt((3xx8.3xx300)/(28xx10^(-3)))=516.8m//s` <br/> `m=1g"mole"=(<a href="https://interviewquestions.tuteehub.com/tag/28-299271" style="font-weight:bold;" target="_blank" title="Click to know more about 28">28</a>)/(6.02xx10^(26))` <br/> On solving, we get `n=2xx10^(27)`</body></html>
Discussion
45316.

Ratio of emissive power of perfectly black

Answer» <html><body><p>4 : <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/>16 : 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> : 1<br/>2 : 1</p>Answer :B</body></html>
Discussion
45317.

What are the dimensions of permittivity?

Answer» <html><body><p>`ML^2T^(-<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^2`<br/>`M^(-1)L^(-<a href="https://interviewquestions.tuteehub.com/tag/3-301577" style="font-weight:bold;" target="_blank" title="Click to know more about 3">3</a>)T^4A^2`<br/>`ML^(-2)T^2A`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/mlt-2163963" style="font-weight:bold;" target="_blank" title="Click to know more about MLT">MLT</a>^(-2)A`</p>Answer :B</body></html>
Discussion
45318.

A combination of two thin lenses in contact is to be made which has the same focal length for blue and red light. . (Such a combination is known as an ' achromatic doublet '). Show that the ratio of their focal lengths (for lengths (for yellow light ) must be equal in magnitude and opposite in sign to the ratio of the dispersive powers of the material of the two lenses. b. Use the results in (a) to suggest a way of removing chromatic aberration of the convex lens of focal length 15 cm , made of flint glass. You are given convexand concave lenses (made of crown glass ) of various focal lengths. The ratio of the dispersive powers of flint glass to crown glass is about 1.5

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/10-261113" style="font-weight:bold;" target="_blank" title="Click to know more about 10">10</a> ` <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>
Discussion
45319.

The mass of an electron 1/1840 part of mass of proton. When they are subjected to a uniform elecric field, they start accelerating(b) If they start from rest and have the same de Brogile wavelength of 1Å then determine the ratio of their kinetic energies.

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> :`lambda_e=h/sqrt(2m_ek_e), lambda_p=h/sqrt(2m_pk_p` <a href="https://interviewquestions.tuteehub.com/tag/since-644476" style="font-weight:bold;" target="_blank" title="Click to know more about SINCE">SINCE</a> these <a href="https://interviewquestions.tuteehub.com/tag/particles-1147533" style="font-weight:bold;" target="_blank" title="Click to know more about PARTICLES">PARTICLES</a> have same <a href="https://interviewquestions.tuteehub.com/tag/wavelength-1450414" style="font-weight:bold;" target="_blank" title="Click to know more about WAVELENGTH">WAVELENGTH</a> `h/sqrt(2m_ek_e)=h/sqrt(2m_pk_p )`<br/>`m_ek_e=m_pk_p `<br/>` k_e/k_p=m_P/m_e=1840`</body></html>
Discussion
45320.

The mass of an electron 1/1840 part of mass of proton. When they are subjected to a uniform elecric field, they start accelerating(a) which of them will have large acceleration?

Answer» <html><body><p></p>Solution :acceleration `a=(qE)/m or a .a <a href="https://interviewquestions.tuteehub.com/tag/prop-607409" style="font-weight:bold;" target="_blank" title="Click to know more about PROP">PROP</a> 1/m` <a href="https://interviewquestions.tuteehub.com/tag/ie-496825" style="font-weight:bold;" target="_blank" title="Click to know more about IE">IE</a> <a href="https://interviewquestions.tuteehub.com/tag/electron-968715" style="font-weight:bold;" target="_blank" title="Click to know more about ELECTRON">ELECTRON</a> will have large acceleration</body></html>
Discussion
45321.

If relative permeability and magnetic susceptibility of paramagnetic substance are mu_(r) and chi_(m) respectively then ......

Answer» <html><body><p>`mu_(r) <a href="https://interviewquestions.tuteehub.com/tag/lt-537906" style="font-weight:bold;" target="_blank" title="Click to know more about LT">LT</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>, chi_(m) lt <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/>`mu_(r) lt 1, chi_(m) gt 0` <br/>`mu_(r) gt 1, chi_(m) lt 0`<br/>`mu_(r) gt 1, chi_(m) gt 0`</p>Answer :D</body></html>
Discussion
45322.

A proton (mass m) accelerated by a potential difference V flies through a uniform transverse magnetic field B. The field occupies a region of space by width 'd'. If alpha ' be the angle of deviation of proton from initial direction of motion (see figure), the value of sin a will be:

Answer» <html><body><p>`qVsqrt( (pd )/(2m))`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/bd-389836" style="font-weight:bold;" target="_blank" title="Click to know more about BD">BD</a> sqrt((q)/( <a href="https://interviewquestions.tuteehub.com/tag/2mvbrbr-1837807" style="font-weight:bold;" target="_blank" title="Click to know more about 2MV">2MV</a>))`<br/>`(B)/(d )sqrt((q)/(2mV))`<br/>`(B )/(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>)sqrt((qd)/(<a href="https://interviewquestions.tuteehub.com/tag/mv-1082193" style="font-weight:bold;" target="_blank" title="Click to know more about MV">MV</a>))`</p>Answer :B</body></html>
Discussion
45323.

What is modulation index? What is importance of modulation index?

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> :The degree to which the 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> is <a href="https://interviewquestions.tuteehub.com/tag/modulated-7696650" style="font-weight:bold;" target="_blank" title="Click to know more about MODULATED">MODULATED</a> is called <a href="https://interviewquestions.tuteehub.com/tag/modulation-1100034" style="font-weight:bold;" target="_blank" title="Click to know more about MODULATION">MODULATION</a> index. The modulation index deermines the strength and quality of the transmitted <a href="https://interviewquestions.tuteehub.com/tag/signal-1207167" style="font-weight:bold;" target="_blank" title="Click to know more about SIGNAL">SIGNAL</a>. When modulation index is high, the reception will be strong and clear.</body></html>
Discussion
45324.

The given figure represents a portion of a wire in a circuit. A current is flowing in the wire in the direcnon shown. Under the convention that is positive charge that flows, the electric field point field in the direction of the charge rent. There will be some charge accumulation at the bend to change the direction of the electric field. What is the direction of the electric field due to charges at the bend?

Answer» <html><body><p><img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/MST_AG_JEE_MA_PHY_V02_C26_E03_025_O01.png" width="30%"/><br/><img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/MST_AG_JEE_MA_PHY_V02_C26_E03_025_O02.png" width="30%"/><br/><img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/MST_AG_JEE_MA_PHY_V02_C26_E03_025_O03.png" width="30%"/><br/><img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/MST_AG_JEE_MA_PHY_V02_C26_E03_025_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> :D</body></html>
Discussion
45325.

A infinitely long solid non-conducting cylinder has radius 'r' and charge density ρ Cm^(-3). Electric field at distance x from its centre is (x lt r)

Answer» <html><body><p>`(<a href="https://interviewquestions.tuteehub.com/tag/px-1173413" style="font-weight:bold;" target="_blank" title="Click to know more about PX">PX</a>)/(3epsilon_(<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/>`(px)/(2epsilon_(0))`<br/>`(px)/(R epsilon_(0))`<br/>`(<a href="https://interviewquestions.tuteehub.com/tag/3px-1862261" style="font-weight:bold;" target="_blank" title="Click to know more about 3PX">3PX</a>)/(t_(0))`</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
45326.

If the amplitude of a simple pendulum is doubled, how many times will the value of its maximum velocity be that of the maximum velocity in initial

Answer» <html><body><p>`1//2`<br/>2<br/>4<br/>`1//4`</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
45327.

There is force of attraction between two unlike charges because lines of force have tendency

Answer» <html><body><p>to <a href="https://interviewquestions.tuteehub.com/tag/shrink-630798" style="font-weight:bold;" target="_blank" title="Click to know more about SHRINK">SHRINK</a> <a href="https://interviewquestions.tuteehub.com/tag/along-1974109" style="font-weight:bold;" target="_blank" title="Click to know more about ALONG">ALONG</a> their length and they are under tension<br/>to intersect each other<br/>to <a href="https://interviewquestions.tuteehub.com/tag/elongate-7387600" style="font-weight:bold;" target="_blank" title="Click to know more about ELONGATE">ELONGATE</a> along their length<br/>none of these</p>Answer :A</body></html>
Discussion
45328.

If a voltage to an X-ray tube is increased to 1.5 times the minimum wavelength (lamda_(min)) of an X-ray continuous spectrum shifts by Delta lamda = 26 pm. The initial voltage applied to the tube is

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/kv-1063110" style="font-weight:bold;" target="_blank" title="Click to know more about KV">KV</a>`<br/>`~~ <a href="https://interviewquestions.tuteehub.com/tag/16-276476" style="font-weight:bold;" target="_blank" title="Click to know more about 16">16</a> kV`<br/>`~~ 50 kV`<br/>`~~ 75kV`</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
45329.

An ammeter and a voltmeter of resistance R are connected in series to a cell of negligible internal resistance. Their readings are A and V respectively. If an other resistance R is connected in parallel with the voltmeter

Answer» <html><body><p>Both A and <a href="https://interviewquestions.tuteehub.com/tag/v-722631" style="font-weight:bold;" target="_blank" title="Click to know more about V">V</a> increases<br/>Both A and V <a href="https://interviewquestions.tuteehub.com/tag/decreases-946143" style="font-weight:bold;" target="_blank" title="Click to know more about DECREASES">DECREASES</a><br/>A decreases but <a href="https://interviewquestions.tuteehub.com/tag/b-387190" style="font-weight:bold;" target="_blank" title="Click to know more about B">B</a> increases<br/>A <a href="https://interviewquestions.tuteehub.com/tag/increase-1040383" style="font-weight:bold;" target="_blank" title="Click to know more about INCREASE">INCREASE</a> but V decreases</p>Answer :D</body></html>
Discussion
45330.

A substance is dipped in liquid, then due to which reason, substances will be invisible ?

Answer» <html><body><p> When <a href="https://interviewquestions.tuteehub.com/tag/substance-1231528" style="font-weight:bold;" target="_blank" title="Click to know more about SUBSTANCE">SUBSTANCE</a> <a href="https://interviewquestions.tuteehub.com/tag/reacts-1178303" style="font-weight:bold;" target="_blank" title="Click to know more about REACTS">REACTS</a> as perfect reflector.<br/>When it absorbs the <a href="https://interviewquestions.tuteehub.com/tag/light-1073401" style="font-weight:bold;" target="_blank" title="Click to know more about LIGHT">LIGHT</a> completely. <br/>When its refractive index is <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/> When refractive indices of substance and liquid are same.</p>Solution :When both have same refractive indiccs, then <a href="https://interviewquestions.tuteehub.com/tag/surface-1235573" style="font-weight:bold;" target="_blank" title="Click to know more about SURFACE">SURFACE</a> doesn.t reflect or refract, hence it will be visible.</body></html>
Discussion
45331.

In a series LCR circuit R = 10 Omega and the impedance Z = 20 Omega. Then the phase difference between the current and the voltage is

Answer» <html><body><p>`<a href="https://interviewquestions.tuteehub.com/tag/60-328817" style="font-weight:bold;" target="_blank" title="Click to know more about 60">60</a>^(@)`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/30-304807" style="font-weight:bold;" target="_blank" title="Click to know more about 30">30</a>^(@)`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/45-316951" style="font-weight:bold;" target="_blank" title="Click to know more about 45">45</a>^(@)`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/90-341351" style="font-weight:bold;" target="_blank" title="Click to know more about 90">90</a>^(@)`</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>
Discussion
45332.

If a current of 3A, flowing in the primary coil is reduced to zero in 10^-3s, the induced e.m.f. in the secondary coil is 15000V. The mutual inductance between the two coils 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_s = M(dI_p)/<a href="https://interviewquestions.tuteehub.com/tag/dt-960413" style="font-weight:bold;" target="_blank" title="Click to know more about DT">DT</a>` <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> <a href="https://interviewquestions.tuteehub.com/tag/15000-275716" style="font-weight:bold;" target="_blank" title="Click to know more about 15000">15000</a> = Mxx3xx10^3` <br/> `therefore M = <a href="https://interviewquestions.tuteehub.com/tag/5h-326479" style="font-weight:bold;" target="_blank" title="Click to know more about 5H">5H</a>`</body></html>
Discussion
45333.

What do you mean by terms 'in phase' ?

Answer» <html><body><p></p>Solution :Let `I_1` and `I_2` be the <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 <a href="https://interviewquestions.tuteehub.com/tag/two-714195" style="font-weight:bold;" target="_blank" title="Click to know more about TWO">TWO</a> <a href="https://interviewquestions.tuteehub.com/tag/beams-894101" style="font-weight:bold;" target="_blank" title="Click to know more about BEAMS">BEAMS</a> having <a href="https://interviewquestions.tuteehub.com/tag/amplitudes-859603" style="font-weight:bold;" target="_blank" title="Click to know more about AMPLITUDES">AMPLITUDES</a> `a_1` and `a_2.` <br/> `I_1/I_2=9/1` <br/> But,`I_1/I_2=a_1^2/a_2^2 `<br/>` therefore a^2_1/a_2^2=9/1` or, `a_1/a_2=3/1` <br/> If `a_max` and `a_min` are the amplitudes are maxima and <a href="https://interviewquestions.tuteehub.com/tag/minima-1097152" style="font-weight:bold;" target="_blank" title="Click to know more about MINIMA">MINIMA</a>. <br/>`a_max/a_min =a_1+a_2/a_1-a_2=3+1/3-1=4/2=2/1` <br/> `I_max/I_min=a^2_max/a^2_min=4/1`</body></html>
Discussion
45334.

Figure shown plane waves refracted for air to water using Huygen.s principle a,b,c,d ,e are lengths on the diagram . The ratio of refractive index of water w.r.t air is

Answer» <html><body><p>a/e<br/>b/e<br/>b/d<br/>d/b</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
45335.

An a.c. circuit has a chock coil L and resistance R. The potential difference across the chocke is v_(L) = 160 V and that across the resistance v_(R) = 120V. Find the virtual value of the applied voltage. If the virtual current in the circuit be 1.0 A, then calculate the total impedance of the circuit. If a direct current be passed in the circuit, then what will be the potential difference in the circuit ?

Answer» <html><body><p><br/></p>Answer :`<a href="https://interviewquestions.tuteehub.com/tag/e-444102" style="font-weight:bold;" target="_blank" title="Click to know more about E">E</a> = 200 <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/z-750254" style="font-weight:bold;" target="_blank" title="Click to know more about Z">Z</a> = 200 <a href="https://interviewquestions.tuteehub.com/tag/omega-585625" style="font-weight:bold;" target="_blank" title="Click to know more about OMEGA">OMEGA</a>, V_(R) = 120 V`</body></html>
Discussion
45336.

Electric field due to an infinite sheet of charge having surface charge density sigma is E. Electric field due to an infinite conducting sheet of same surface density of charge is

Answer» <html><body><p>E/2<br/>E<br/>2E<br/> 4E</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
45337.

A radioactive element has half life period 800 years. After 6400 years what amount will remain ?

Answer» <html><body><p>`1/2`<br/>`1/16`<br/>`1/8`<br/>`1/256`</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
45338.

A wheel of mass 1000kg has M,I. of 160 kgm^2 about its own axis . the radius of gyration is

Answer» <html><body><p>0.24 m<br/>0.34 m<br/>0.4 m<br/>0.45 m</p>Answer :A</body></html>
Discussion
45339.

Unpolarised light is incident on a plane surface heaving refractive index sqrt3. The angle of incidence at which reflected and refracted rays would become perpendicular to each other is

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;`15^(@)`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/30-304807" style="font-weight:bold;" target="_blank" title="Click to know more about 30">30</a>^(@)`<br/>`45^(@)`<br/>`60^(@)`</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> :Hint : <a href="https://interviewquestions.tuteehub.com/tag/reflected-2982114" style="font-weight:bold;" target="_blank" title="Click to know more about REFLECTED">REFLECTED</a> and refracted rays are mutually perpendicular when <a href="https://interviewquestions.tuteehub.com/tag/angle-875388" style="font-weight:bold;" target="_blank" title="Click to know more about ANGLE">ANGLE</a> of incident is the polarizing angle i.e., `i=i_(p)=tan^(-1)(n)=tan^(-1)(sqrt3)=60^(@).`</body></html>
Discussion
45340.

Figure shows the variation of intensity of magnetisation vecM versus the applied magnetic field intensity vecH for two materials A and B: (a) Identify the materials A and B. (b) Why does the material B, have a larger susceptibility than A for a given field at constant temperature ?

Answer» <html><body><p></p>Solution :(a) Material A is <a href="https://interviewquestions.tuteehub.com/tag/diamagnetic-950823" style="font-weight:bold;" target="_blank" title="Click to know more about DIAMAGNETIC">DIAMAGNETIC</a> because its magnetisation is negative <br/>Material B is <a href="https://interviewquestions.tuteehub.com/tag/paramagnetic-2210688" style="font-weight:bold;" target="_blank" title="Click to know more about PARAMAGNETIC">PARAMAGNETIC</a> having positive magnetisation . <br/>(b) Magnetic susceptibility ` x = M/H` and its <a href="https://interviewquestions.tuteehub.com/tag/value-1442530" style="font-weight:bold;" target="_blank" title="Click to know more about VALUE">VALUE</a> is given by slope of M - H <a href="https://interviewquestions.tuteehub.com/tag/curve-941741" style="font-weight:bold;" target="_blank" title="Click to know more about CURVE">CURVE</a>. As slope of curve for material B is greater, hence B has a large susceptibility than A for a given <a href="https://interviewquestions.tuteehub.com/tag/field-987291" style="font-weight:bold;" target="_blank" title="Click to know more about FIELD">FIELD</a> at constant temperature.</body></html>
Discussion
45341.

The position of an object moving along x-axis is given by x=a+bt^(2) where a =8.5 m, b=2.5 ms^(-2) and t is measured in seconds.Then which of the following is true ?

Answer» <html><body><p><a href="https://interviewquestions.tuteehub.com/tag/velocity-1444512" style="font-weight:bold;" target="_blank" title="Click to know more about VELOCITY">VELOCITY</a> at t=2 <a href="https://interviewquestions.tuteehub.com/tag/sec-1197209" style="font-weight:bold;" target="_blank" title="Click to know more about SEC">SEC</a> is zero<br/>Average velocity between t=2,t=4 sec is <a href="https://interviewquestions.tuteehub.com/tag/15-274069" style="font-weight:bold;" target="_blank" title="Click to know more about 15">15</a> m/s<br/>Velocity at t=4 sec is <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/s<br/>All the above are true</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
45342.

In the study of transistor as an amplifier alpha=I_C/I_E and beta=I_C/I_B where I_C,I_E and I_Bare the collector, emitter and base currents respectively. The correct relation between’ alpha and betais given by

Answer» <html><body><p>`<a href="https://interviewquestions.tuteehub.com/tag/beta-2557" style="font-weight:bold;" target="_blank" title="Click to know more about BETA">BETA</a>=(1-<a href="https://interviewquestions.tuteehub.com/tag/alpha-858274" style="font-weight:bold;" target="_blank" title="Click to know more about ALPHA">ALPHA</a>)/alpha`<br/>`beta=alpha/(1-alpha)`<br/>`beta=(1+alpha)/alpha`<br/>`beta=alpha/(1+alpha)`</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
45343.

A car moving on a straight road accelerates from a speed of 4.1 m/s to a speed of 6.9 m/s in 5.0 s.What was its average acceleration?

Answer» <html><body><p>`0.56 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>)`<br/>`1.56 m//s^(2)`<br/>`5.6 m//s^(2)`<br/>`1.2 m//s^(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> :A</body></html>
Discussion
45344.

Who are the pioneers in the field of electromagnetic waves ?

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/maxwell-557203" style="font-weight:bold;" target="_blank" title="Click to know more about MAXWELL">MAXWELL</a> (1865),<a href="https://interviewquestions.tuteehub.com/tag/hertz-1019743" style="font-weight:bold;" target="_blank" title="Click to know more about HERTZ">HERTZ</a> (1887),<a href="https://interviewquestions.tuteehub.com/tag/marconi-554974" style="font-weight:bold;" target="_blank" title="Click to know more about MARCONI">MARCONI</a>(1896,1899).</body></html>
Discussion
45345.

The C.G.S, unit of universal gravitational constant is

Answer» <html><body><p>`6.67xx10^-11Nm^2//kg^2`<br/>`66.73xx10^-11Nm^2//kg^2`<br/>`6.67xx10^-8Nm^2//kg^2`<br/>`6.673xx10^-13Nm^2//kg^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> :A</body></html>
Discussion
45346.

Three is another useful system of units, besides the SI/mksA system, called the cgs (centimeter-gram -second) system, Coulumb's law is givenby F = (Qq)/(r^(2)) hat(r ) where the distance r is measured in cm (=10^(-2)m), F in dynes (=10^(-5) N) and the charges in electrostatic units (es units), where1 esunit of charge =(1)/([3]) xx 10^(-9) C The number [3] actually ariesfrom the speed of light in vacumm which is now taken to be exactly given by c = 2.99792458xx10^(8) m//s. An approximatevalue of c thenis c = [3] xx10^(8) m//s. (i) Show that the coulomb law in cgs units yields 1 esu of charge = 1 (dyn e)^(1//2)cm. Obtain the dimensious of units of charge in terms of mass M, length L and time T. Show that it is given in termsof fractional powers of M and L. (ii) Write 1 esu of charge = xC, wherex is a dimenionless number. Show that this gives (1)/(4pi in_(0)) = (10^(-9))/(x^(2)) (N.m^(2))/(C^(2)) Withx = (1)/([3]) xx10^(-9), we have (1)/(4pi in_(0)) = [3]^(2) xx10^(9) (Nm^(2))/(C^(2)) or (1)/(4pi in_(0)) = (2.99792458)^(2) xx 10^(9) (Nm^(2))/(C^(2)) (exactly).

Answer» <html><body><p></p>Solution :(i) From`F = (Qq)/(r^(2))` <br/> `<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/dyn-2596635" style="font-weight:bold;" target="_blank" title="Click to know more about DYN">DYN</a> e = ((1" esu of charge")^(2))/((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>)^(2))` <br/> `:.` 1 esu of charge`= (1 dyn e)^(1//2) <a href="https://interviewquestions.tuteehub.com/tag/xx-747671" style="font-weight:bold;" target="_blank" title="Click to know more about XX">XX</a> 1cm = F^(1//2). L = (MLT^(-2))^(1//2)` L or 1 esu of charg e ` = M^(1//2) L^(3//2) T^(-1)`. <br/> Thus esu of charge is represented in terms of fractional powers`: (1)/(2) of M and (3)/(2) of L`<br/>(ii) Let 1 esu fo charge = x C, where x is a dimenionless number<br/> Coulomb forceon two charges, each of magnitude1 esu separatedby `1 cm is 1 dyne = 10^(-<a href="https://interviewquestions.tuteehub.com/tag/5-319454" style="font-weight:bold;" target="_blank" title="Click to know more about 5">5</a>) N`. <br/> This situation is equivalent to two charges of magnitude x C separated by `10^(-2)m`. <br/> `:. F = (1)/(4pi in_(0)) (x^(2))/((10^(-2))^(2)) = 1 dyne = 10^(-5) N :. (1)/(4pi in_(0)) = (10^(-9))/(x^(2)) (N m^(2))/(C^(2))`<br/> Taking`x = (1)/(|3| xx10^(9))`, we get, `(1)/(4pi in_(0))= 10^(-9)xx |3| xx10^(18) (Nm^(2))/(C^(2)) = 9xx10^(9) (Nm^(2))/(C^(2))`<br/> If `|3| rarr 2.99792458`, we get`(1)/(4pi in_(0)) = 8.98755xx10^(9) Nm^(2) C^(-2)`</body></html>
Discussion
45347.

Two rods of lengths L_1 and L_2 are made of materials whose co-efficient of linear expansion arealpha _1 and alpha_2,If the difference between two lengths is independent of temperature , then

Answer» <html><body><p>a)`(L_1//L_2) = alpha_1/alpha_2`<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>)`(L_1/L_2)= alpha_2/alpha_1`<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>)`L_1^2alpha_1=L_2^2alpha_2`<br/>d)`alpha_1^2L_1 =alpha_2^2L_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> :B</body></html>
Discussion
45348.

A coil of N turns and area A is placed in a uniform transverse magnetic field B in such a way that vecA and vecB are parallel. If the plate in turned through 180^@ about its one of the diameter in 2 seconds then the (i) change of magnetic flux through the coil is ? (ii) rate of change of flux is the coil 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> :`Deltaphi=phi_2-phi_1` <br/> `=NBA (<a href="https://interviewquestions.tuteehub.com/tag/cos-935872" style="font-weight:bold;" target="_blank" title="Click to know more about COS">COS</a> theta_2-costhata_1)` <br/> `= NBA(cos180^@-cos0)` <br/> =NBA[-1-1] <br/> =-2NBA <br/> (ii)Rate of charge of flux is <br/> `(Deltaphi)/(Deltat)=(-2NBA)/(<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/> =-NBA</body></html>
Discussion
45349.

A cannon fires successively two shells with velocity v_(0) = 250 m//s, the first at the angle therefore= 60^(@) and the second at the angle q_(2) = 45^(@)to the horizontal, the azimuth being the same. Neglecting the air drag, find the time interval between firings leading to the collision of the shells.

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> :Let the first shell travel for time `t_(1)` and second fortime `t_(2)` , before they collide . <br/>Both the shells must travel equal horizontal and <a href="https://interviewquestions.tuteehub.com/tag/vertical-726181" style="font-weight:bold;" target="_blank" title="Click to know more about VERTICAL">VERTICAL</a> distances to collide. <br/>For horizontal motion `v_(0) cos theta_(1) .t_(1) = v_(0) cos theta_(2) t_(2)` <br/>`i.e., (t_(1))/(t_(2)) =(cos theta)/(cos theta_(2)) , (t_(1))/(t_(2)) = (cos <a href="https://interviewquestions.tuteehub.com/tag/45-316951" style="font-weight:bold;" target="_blank" title="Click to know more about 45">45</a>^(@))/( cos <a href="https://interviewquestions.tuteehub.com/tag/60-328817" style="font-weight:bold;" target="_blank" title="Click to know more about 60">60</a>^(@)) = (1//sqrt(2))/(1//2)t_(2)` <br/> `i.e.,(t_(1))= sqrt(2) t_(2)` <br/> For vertical motion , <br/>`v_(0) sin theta_(1). t_(1)- (1)/(2) "gt"_(1)^(2) = v_(0) sin theta_(2) . t_(2) = (1)/(2) "gt"_(2)^(2) (or) v_(0) sin 60^(@),t_(1) - (1)/(2)"gt"_(1)^(2) = v_(0) sin 45^(@) .t_(2) - (1)/(2) "gt"_(2)^(2)` <br/> (or) `v_(0) ( sin 60^(@) t_(1) - sin 45^(@)t_(2)) = (g)/(2) (t_(1)^(2) -t_(2)^(2))` <br/> Puttingvalues`250((sqrt(3))/(2)sqrt(2)t_(2)- (1)/(sqrt(2))t_(2)) = (9.8)/(2)(2t_(2)^(2) - t_(2)^(2))<a href="https://interviewquestions.tuteehub.com/tag/rarr-1175461" style="font-weight:bold;" target="_blank" title="Click to know more about RARR">RARR</a> 250((sqrt(6) - sqrt(2))/(2)) t_(2)= 4.9 t_(2)^(2)` <br/>`t_(2) = (250(2.45-1.41))/(2 xx 4.9) (or) t_(2) = (250xx 1.04)/(9.8)= 26.7 s rArr t_(1) = sqrt(2) t_(2) = 1.414 xx 26.7= 37.8s` <br/> Timeinterval `t_(1) - t_(2) = 37.8s - 26.7 s = 11.1 s`</body></html>
Discussion
45350.

What amount of inpurity of atomic density in added toform N-type semiconductor in Ge semiconductor of conductivity sigma is 5Omega^(-1)cm^(-1) Mobility of electron in N-type semiconductoris 3900 cm^(2)V^(-1)s^(-1). Ignore conductivitydue to hole. (e=1.6xx10^(-19)C)

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>.25xx10^(21)m^(-3)` <br/>`4.007xx10^(21)m^(-3)` <br/>`8013xx10^(21)m^(-3)` <br/>`8.013xx10^(21)m^(-3)` </p>Solution :`8.013xx10^(21)m^(-3)`<br/> `sigma=5Omega^(-1)cm^(-1)=500Omega^(-1)m^(-1)` <br/> `mu_(e )=3900cm^(2)<a href="https://interviewquestions.tuteehub.com/tag/v-722631" style="font-weight:bold;" target="_blank" title="Click to know more about V">V</a>^(-1)s^(-1)=0.39m^(2)V^(-1)s^(-1)` <br/> Now `sigma=en_(e )mu_( e)` <br/> `therefore n_(e )=(sigma)/(emu_(e ))` <br/> `therefore n_(e )=(500)/(1.6xx10^(-19)xx0.39)` <br/> `therefore n_(e )~~8.013xx10^(21)m^(-3)`</body></html>
Discussion