NEET UG Physics Electromagnetic Induction MCQs

11. An electron moves along the line AB,which lies in the same plane as a circular loop of conducting wires as shown in figure. What will be the direction of current induced if any, in the loop ?

(a) No current will be induced

(b) The current will be clockwise

(c) The current will be anticlockwise

(d) The current will change direction as the electron passes by

12. A circular loop of radius R carrying current I lies in X-Y plane with its centre at origin. The total magnetic flux through x-y plane is ___

(a) Directly proportional to I (b) Directly proportional to R

(c) Directly proportional to R² (d) zero

(a) Increases
(b) decreased
(c) Remain same
(d) depending on whether the semicircle bulge is towards the resistance or away from it.

14. Two similar circular loops carry equal currents in the same direction.On moving the coils further apart, the electric current will
(a) Remain unchanged
(b) Increasing in both
(c) Increasing in one decreasing in other
(d) Decreasing in both

15. When the number of turns in a coil is make four time without any change in length of the coil, its self inductance becomes 
(a) unchanged
 (b) two times
(c) four times
(d) sixteen times

16. A metal road moves at a constant velocity in a direction perpendicular to its length & a constant uniform magnetic field too. Select the correct statement (s) from the following.
(a) The entire rod is at the same electrical potential
(b) There is an electric field in the rod
(c) The electric polential is highest at the centre of the rod.
(d) The electric polential is lowest at the centre of the rod.

19. Two coils of self inductances 2 mH & 8 mH are placed so close togather that the effective flux in one coil is completely half with the other.The mutual inductance between these coils is ____
(a) 4 mH
(b) 6 mH
 (c) 2 mH
(d) 16 mH

20. In circular coil. when no. of turns is doubled & resistance becomes half of the initial then inductance becomes ____
(a) 4 times
 (b) 2 times
 (c) 8 times
 (d) No change

43. The core of a transformer is laminated so that ____
(a) Ratio of I/p & O/p voltage increases
(b) Rusting of core may be stopped
(c) Energy loss due to eddy current may be reduced
(d) Change in flux is increased

44. In transformer, core is made of soft iron to reduce _____
(a) Hysterlsis losses
(b) Eddy current losses
(c) Force opposing current
 (d) the weight

45. An ideal transformer has 1:25 turn ratio. The peak value of the ac is 28 V. The rms ms secondary voltage is nearest to _____
(a) 50 V
(b) 70 V
(c) 100 V
(d) 40 V

46. A primary winding of transformer has 500 turns whereas its secondary has 5000 turns. Primary is connected to ac supply of 20V, 50Hz The secondary output of ____
(a) 200V, 25 Hz
 (b) 200 V, 50Hz
(c) 2 V, 100 Hz (d) 2V, 50 Hz

47. A step down transformer is connected to main supply 200 V to operate a 6V, 30 w bulb. The current in primary is ____
(a) 3A
(b) 1.5 A
(c) 0.3 A
(d) 0.15 A

50. A coil of inductance 8.4 mH and resistance 6Ω is connected to a 12 V battery. The current in the coil is 1A in the time 
(a) 500 sec
(b) 20 sec
 (c) 35 ms
(d) 1 ms

51. Alternating current can not be measured by dc ammeter because,
(a) ac can not pass through dc ammeter
(b) Average value of complete cycle is zero
(c) ac is virtual
(d) ac changes its direction

52. The resistance of a coil for dc is in ohms. In ac, the resistance
(a) will remain same
 (b) will increase
(c) will decrease
(d) will be zero

73. Same current is flowing in two alternating circuits.The first circuits contains only inductance and the other contains only a capacitor. If the frequency of the emf of ac is increased the effect on the value of the current will be.
(a) Increase in the first circuit and dicrease in other
(b) Increase in both the circuit
(c) Decrease in both the circuit
(d) Decrease in the first and increase in other