question_answer

A solid metal cube of edge length 2 cm is moving in a positive y-direction at a constant speed of 6 m/s. There it?, a uniform magnetic field of 0.1 T in the positive z- direction. The potential difference between the two faces of the cube perpendicular to the x-axis, is - [JEE Main Online Paper (Held On 10-Jan-2019 Morning]

A) 2 mV                           

B) 12 mV

C) 6 mV               

D)   1 mV

Correct Answer: B

Solution :

Due to magnetic force on electron charge separation get develop as shown in figure At steady state \[eVB\,\,=\,\,eE\] \[E=VB\] Potential difference between two faces \[=\text{ }EL-VBL\] \[=\text{ }0.1\times 6\times 2\times {{10}^{-2}}\] \[=\text{ }12\text{ }mV\]