Assertion: If an electron, while coming vertically from outerspace, enter the earth's magnetic field, it is deflected towards west.
Reason: Electron has negative charge.

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 the assertion and reason both are false.

Answer

B

Explanation

We know that the direction of the earth’s magnetic field is towards north and the velocity of electron is vertically downward. Applying Fleming’s left hand rule, the direction of force is towards west. Therefore, an electron coming from outer space will be deflected towards west.