Subject: Physics, asked on 19/5/18
Subject: Physics, asked on 16/5/18

## Why/How will the ring expand in the following case? Give reasoning Q.26. A conducting loop carrying a current I is placed in xy-plane. A uniform magnetic field pointing into Z-direction is switched on. The loop will have a tendency to a. contract b. expand c. move towards + ve X-axis d. move towards - ve X-axis

Subject: Physics, asked on 25/4/18

## please derive this equation Q. $F=-\frac{∆U}{∆x}$

Subject: Physics, asked on 24/4/18

## Solve this :  11. An iron rod of length 100 cm and 10 cm2 cross-section is heated from 0oC to 100o If it is not allowed to bend or expand, what force is developed in it ? Given that Y -1012dyne/cm2 and a = 10-5/oC. (a) 108 dyne  (b) 109 dyne (c) 1010 dyne (d) 1011 dyne

Subject: Physics, asked on 23/4/18

## Solve this: Q.16. If the terminal speed of a sphere of gold [density = 19.5 g/$c{m}^{3}$] is 0.2 m/s in a viscous liquid [density = 1.5 g/$c{m}^{3}$], find  the terminal speed of a sphere of silver [density = 10.5 g/$c{m}^{3}$] of the same size in the same liquid. (a) 0.133 m/s (b) 0.1 m/s (c) 0.2 m/s (d) 0.4 m/s

Subject: Physics, asked on 21/4/18

## The ans given is four times, but if we increase the number of turns by two times without change in length of the solenoid, shouldn't the radius also decrease by 2 times? Hence, won't the self inductance become eight times?: 26. When the number of turns in a solenoid are doubled without any change in the length of the solenoid, it self inductance becomes. (1) Half              (2) Double           (3) Four Times              (4) Eight times.

Subject: Physics, asked on 21/4/18

## A copper rod of length l is rotating about mid point perpendicular to the magnetic field B with constant angular velocity omega the induces emf between the two ends is?....Ans is zero, please explain why

Subject: Physics, asked on 18/4/18

## Pls answer this Carnot engine mains question Q 5. Two Carnot engines A and B are operated in series. Engine A receives heat from a reservoir at 600 K and rejects heat to a reservoir at temperature T. Engine B receives heat rejected by engine A and in turn rejects it to a reservoir at 100 K. If the efficiencies of the two engines A and B are represented by $\eta$A and $\eta$B , respectively, then what is the value of $\frac{{\eta }_{B}}{{\eta }_{A}}?$ Option :

Subject: Physics, asked on 17/4/18

## Ques. A solenoid of inductance 2H carries a current of 1 A. What is the magnetic energy stored in a solenoid ? (1) 2 J                               (2) 1 J (3) 4 J                               (4) 5

Subject: Physics, asked on 16/4/18

## Pls explain this question: Illustration 5. Five point charges, each of value +q are placed of five vertices of a regular hexagon of side L. What is the magnitude of the force on a point charge of value-q placed at the centre of the hexagon ?

Subject: Physics, asked on 16/4/18

## 41. When a wave passes from one medium to another, there is change in (a) frequency and velocity (b) frequency and wavelength (c) wavelength and velocity (d) frequency, wavelength and velocity 42. A fork gives 5 beats with a 40 cm length of sonometre wire. If the length ofthe wire is shortened by 1 cm, the number of beats is still the same. The frequency of the fork is (a) 385 Hz (b) 600 Hz (c) 395 Hz (d) 400 Hz

Subject: Physics, asked on 12/4/18

## Solve qus no. 38 ​Q38. The heart beat of a person is 90 per minute. The frequency is               (a) 90 Hz                                          (b) 60 Hz              (c) 1.33 Hz                                       (d) 1.5 Hz

Subject: Physics, asked on 10/4/18

## Q. Find the EMF induced in metal loop when it moves in non-uniform magnetic field

Subject: Physics, asked on 10/4/18

## Q. ​A conducting rod moves towards right with constant velocity v in uniform transverse magnetic field. Graph between force applied by the external agent v/s velocity and power supplied by the external  agent v/s velocity..  (l) Straight. line, parabola  (2) Parabola, Straight line  (3) Straight line, Straight line  (4) Parabola, Parabola

Subject: Physics, asked on 10/4/18

## Q. A rectangular loop 10 cm and 3 cm moving out of a region of uniform magnetic field of 0.5 T directed normal to the loop. If we want to move loop with a constant velocity 1 cm/sec, then what is the required mechanical force? (Resistance of loop = 1 m ohm)   (1) 2.25 x ${10}^{-3}$N  (2) 4.5 x ${10}^{-3}$ N (3) 9 x ${10}^{-3}$N  (4) 1.25 x ${10}^{-3}$ N

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