Question

The ratio of specific charge of a proton and an $\alpha -$ particle is ______.

• A. $2:1$
• B. $1:2$
• C. $1:4$
• D. $1:1$

Answer 1

The correct option is B $1:2$

Answer:-

Specific charge = $\frac{Charge}{Mass}$ ratio.

Let the specific charge of proton be p.

Therefore specific charge of alpha particle = 2p ( $\because \alpha$ particle has 2 protons and 2 neutrons, neutrons have same mass as protons but charge is zero)

Therefore, ratio of specific charge of protons to alpha particles = $\frac{p}{2p}=\frac{1}{2}\Rightarrow 1:2$