JEE Main & Advanced
Physics
Electro Magnetic Induction
Question Bank
Self Evaluation Test - Electromagnetic Induction
question_answer
A vertical ring of radius r and resistance R falls vertically. It is in contact with two vertical rails which are joined at the top. The rails are without friction and resistance. There is a horizontal uniform magnetic field of magnitude B perpendicular to the plane of the ring and -the rails. When the speed of the ring is v, the current in the top horizontal of the rail section is
A)0
B)\[\frac{2Brv}{R}\]
C)\[\frac{4Brv}{R}\]
D)\[\frac{8Brv}{R}\]
Correct Answer:
D
Solution :
[d] \[I=\frac{2Brv}{R/2}=\frac{4Brv}{R}\] Current in the top horizontal\[=2I=\frac{8Brv}{R}\]