Question:
A charged particle enters a uniform magnetic field with a velocity v at right angles to the field. It moves in a circle with period T. An identical particle enters the field with a velocity v/2. What

A charged particle enters a uniform magnetic field with a velocity v at right angles to the field. It moves in a circle with period T. An identical particle enters the field with a velocity v/2. What is its period? (A) 4T (B)2T (C)T (D)T/2