A : Cyclotron does not accelerate electron.
R : Mass of the electron is very small.

Options

A. Assertion is true, reason is true and reason is the correct explanation for assertion.
B. Assertion is true, reason is true but reason is not the correct explanation for assertion.
C. Assertion is true, reason is false.
D. Assertion is false, reason is true.

Answer

A

Explanation

Cyclotron is an instrument which can accelerate heavy charged particles like proton and `alpha`-particles. It can not accelerate higher particles like electron, because if electron is accelerated than it will obtain a speed equal to speed of light and a substaintial change is seen in its mass. Both these statement and reason are true and reason is the correct for statement, so option (A) is true.