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1.	In the previous problem, what will be force with which system moves? `(Use (sqrt2) =1.4)`A. `3.05N`B. `4.0 N`C. `0.5 N`D. `1.0 N`
Answer» Correct Answer - C

2.	Suppose the `19 Omega` resistor of the previous problem is disconnected. Find the current through `P_2 Q_2` in the two situations (a) and (b) of that problem.A. zeroB. 3 mAC. 1 mAD. None of these
Answer» Correct Answer - A

3.	In a cylindrical region of radius a, magnetic field exists along its axis but the direction of magnetic field is opposite in the four quadrants of the region as shown in Fig. A or AB rotates with its end A at the centre of magnetic field and other end B slides on a smooth wire at the periphery of the region of magnetic field. At t = 0 the rod was situated along the +X direction. Find and plot the time dependence of the current in the resistance R when rotates with a constant angular acceleration `(alpha)`A. B. C. D.
Answer» Correct Answer - A

4.	In a cylindrical region of radius a, magnetic field exists along its axis but the direction of magnetic field is opposite in the four quadrants of the region as shown in Fig. A or AB rotates with its end A at the centre of magnetic field and other end B slides on a smooth wire at the periphery of the region of magnetic field. At `t = 0` the rod was situated along the +X direction. Find and plot the time dependence of the current in the resistance R when rod rotates with a constant angular velocity `(omega)`.A. B. C. D.
Answer» Correct Answer - A

5.	A rectangular wire frame of dimensions `(0.25 xx 2.0 m)` and mass 0.5 kg falls from a height 5m above a region occupied by uniform magnetic field of magnetic induction 1 T. The resistance of the wire frame is `1/8 (Omega)`. Find time taken to completely enter into the field isA. 0.2sB. 1sC. 2.2sD. `sqrt((1)/(5))s`
Answer» Correct Answer - A

6.	A uniform conducting ring of mass `pi` kg and radius 1 m is kept on smooth horizontal table. A uniform but time varying magnetic field `B = (hat (i) + t^(2) hat (j))T` is present in the region, where t is time in seconds. Resistance of ring is `2 (Omega)`. Then Net magnetic field (in Newton) on conducting ring as function of time isA. `2 pi^(2)t`B. `2 pi^(2)t^(2)`C. `2 pi^(2)t^(3)`D. zero
Answer» Correct Answer - D

7.	A uniform conducting ring of mass `pi` kg and radius 1 m is kept on smooth horizontal table. A uniform but time varying magnetic field `B = (hat (i) + t^(2) hat (j))T` is present in the region, where t is time in seconds. Resistance of ring is `2 (Omega)`. Then Heat generated (in kJ) through the ring till the instant when ring start toppling isA. `(1)/(3 pi)`B. `(2)/(pi)`C. `(2)/(3 pi)`D. `(1)/(pi)`
Answer» Correct Answer - C

8.	A uniform conducting ring of mass `pi` kg and radius 1 m is kept on smooth horizontal table. A uniform but time varying magnetic field `B = (hat (i) + t^(2) hat (j))T` is present in the region, where t is time in seconds. Resistance of ring is `2 (Omega)`. Then Time (in second) at which ring start toppling isA. `(10)/(pi)`B. `(20)/(pi)`C. `(5)/(pi)`D. `(25)/(pi)`
Answer» Correct Answer - A

9.	Consider the situation shown in . The wire PQ has a negligible resistance and is made to slide on the three rails with a constant speed of `5 cm s^(-1)` . Find the current in the `10 Omega` resistor when the switch S is thrown to (a) the middle rail (b) the bottom rail. A. zeroB. 2 mAC. 1 mAD. None of these
Answer» Correct Answer - D

10.	A stationary circular loop of radius a is located in a magnetic field which varies with time from `t = 0 to t = T` according to law `B = B_(0) t(T - t)`. If plane of loop is normal to the direction of field and resistance of the loop is R, calculate amount of heat generated in the loop during this interval.A. `(pi^(2)a^(4)B_(0)^(2)T^(3))/(3R)`B. `(pi^(2)a^(4)B_(0)^(2)T^(3))/(R)`C. `(3pi^(2)a^(4)B_(0)^(2)T^(3))/(R)`D. None of these
Answer» Correct Answer - A

11.	L is a circular loop (in y-z plane) carrying an anticlockwise current. P is a point on its axis OX dl is an element of length on the loop at a point A on it. The magnetic field at P A. due to L is directed along OX.B. due to kl is directed along OX.C. due to dl is perpendicular to AP in upwards directionD. due to dl is perpendicular to AP in downwards direction
Answer» Correct Answer - A::D

12.	Consider the situation shown Fig. There present a magnetic field B = 1 T which is perpendicular to plane of paper. The wire `P_(2), Q_(2)` are made to slide on the rails with the same speed `5 cm //s`. Find the electric current in the `19 (Omega)` resistance if Both the wires move towards rightA. `0.2 mA`B. `0.3 mA`C. `0.1 mA`D. None of these
Answer» Correct Answer - C

13.	A square wire loop with 2 m sides is perpendicular to a uniform magnetic field, with half the area of the loop in the field (see Fig.) The loop contains a 20 V battery with negligible internal resistance. If the magnitude of the field varies with time according to `B = (2 + 5t)`, with B in tesla and t in second. What is the total emf in the circuit ?A. 10 VB. 20 VC. 30 VD. None of these
Answer» Correct Answer - C

14.	Four long wires each carrying current I as shown in Fig. are placed at points A, B, C and D. Find the magnitude and direction of magnetic field at the centre of the square.A. `(mu_(0))/(4 pi) ((I)/(a))` along Y-axisB. `(mu_(0))/(4 pi) ((4I)/(a))` along X-axisC. `(mu_(0))/(4 pi) ((4I)/(a))` along Y-axisD. None of these
Answer» Correct Answer - C

15.	The switches in figure and are closed at `=0` and reopended after al long time at `t = t_0`. A. the charge on C just after t =0 is ECB. the charge on C long after t=0 is ECC. the current in L just before `t =t_(0) is E//R`D. the current in L long after `t =t_(0) is E//R`
Answer» Correct Answer - B::C

16.	An indcutor having self inductance L with its coil resistance R is connected across a battery of emf `elipson`. When the circuit is in steady state t = 0, an iron rod is inserted into the inductor due to which its inductance becomes nL (ngt1). After insertion of rod which of the following quantities will change with time? (1) Potential difference across terminals A and B (2) Inductance (3) Rate of heat produced in coilA. only (1)B. (1) and (3)C. only (3)D. (1), (2) and (3)
Answer» Correct Answer - C

17.	An indcutor having self inductance L with its coil resistance R is connected across a battery of emf `elipson`. When the circuit is in steady state t = 0, an iron rod is inserted into the inductor due to which its inductance becomes nL (ngt1). after insertion of rod, current in the circuit:A. Increases with timeB. Decreases with timeC. Remains constant with timeD. First decreases with time then becomes constant
Answer» Correct Answer - A