Question

A proton, a deuteron and an $\alpha$-particle accelerated through the same potential difference enter a region of uniform magnetic field, moving at right angles to $B$. What is the ratio of their K.E.?

• A. 2:01:01
• B. 2:02:01
• C. 1:02:01
• D. 1:01:02

Answer 1

Answer: (D)

1:01:02

Answer 2

K.E. gained by charged particle of charge q when accelerated under a potential difference $V$ will be $E_k = qV$
For a given $V,E_k \propto q$
For proton, deuteron and $\alpha$-particle, the ratio of charges is 1 : 1 : 2.