With a standard rectangular bar magnet, the time period in the uniform magnetic field is `4 sec`. The bar magnet is cut parallel to its length into `4` equal pieces. The time period in the uniform magnetic field when the piece is used (in sec) (bar magnet breadth is small)

Options

A. 16
B. 8
C. 4
D. 2

Answer

C

Explanation

`T=2pisqrt(I/(MB)),I=m/12(l^(2)+b^(2))`