A constant magnetic field of 1T is applied in the x > 0 region. A metallic circular ring of radius 1m is moving with a constant velocity of 1 m/s along the x-axis. At t = 0s, the centre of O of the ring is at x = $$-$$1m. What will be the value of the induced emf in the ring at t = 1s? (Assume the velocity of the ring does not change.)
A
1V
B
2$$\pi$$V
C
2V
D
0V
Explanation
emf = BLV
= 1 . (2R) . 1
= 2V
2
JEE Main 2021 (Online) 27th August Morning Shift
MCQ (Single Correct Answer)
Two ions of masses 4 amu and 16 amu have charges +2e and +3e respectively. These ions pass through the region of constant perpendicular magnetic field. The kinetic energy of both ions is same. Then :
A
lighter ion will be deflected less than heavier ion
B
lighter ion will be deflected more than heavier ion
A bar magnet is passing through a conducting loop of radius R with velocity $$\upsilon $$. The radius of the bar magnet is such that it just passes through the loop. The induced e.m.f. in the loop can be represented by the approximate curve :
A
B
C
D
Explanation
$$\to$$ When magnet passes through centre region of solenoid, no current / Emf is induced in loop.
$$\to$$ While entering flux increases so negative induced emf
$$\to$$ While leaving flux decreases so positive induced emf.
4
JEE Main 2021 (Online) 26th August Evening Shift
MCQ (Single Correct Answer)
A light beam is described by $$E = 800\sin \omega \left( {t - {x \over c}} \right)$$. An electron is allowed to move normal to the propagation of light beam with a speed of 3 $$\times$$ 107 ms$$-$$1. What is the maximum magnetic force exerted on the electron?