Question

The particle which has no charge and negligible rest mass is

• A. $\sigma$-meson
• B. K-meson
• C. Positron
• D. Neutrino

Answer 1

The correct option is D Neutrino

$\pi$- meson can have positive, negative or neutral charge and they have mass of 139.6 $M\frac{eV}{C^2}$
K - meson can have positive, negative or neutral charge and they have mass of 492.6 $M\frac{eV}{C^2}$
Positron have +1 charge and mass of 0.51 $M\frac{eV}{C^2}$
Neutrino have no charge and zero rest mass