Statement - 1 : If an electron is not deflected while passing through a certain region of space, then only possibility is that there is no magnetic region. Statement - 2 : Magnetic force is directly proportional to the magnetic field applied.

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.

Answer

D

Explanation

In this case we can not be sure about the absence of the magnetic field because if the electron is moving parallel to the direction of magnetic field, the angle between velocity and applied magnetic field is zero (F = 0). Then also electron passes without deflection. Also `F = ev B sin theta implies F prop B`