JEE Main 2007 Physics question
A current I flows along the length of an infinitely long, straight, thin walled pipe. Then
- (1)the magnetic field is zero only on the axis of the pipe
- (2)the magnetic field is different at different points inside the pipe
- (3)the magnetic field at any point inside the pipe is zeroCorrect
- (4)the magnetic field at all points inside the pipe is the same, but not zero
Answer: (3)
Solution
By Ampère's law, a circular loop inside the pipe encloses no current, and by symmetry everywhere inside, option (3).
Question ID VK-038913