Question

Arrange the three natural radiations in decreasing order of penetration .

• A. alpha, beta, and gamma
• B. beta, gamma, and alpha
• C. gamma, alpha, and beta
• D. gamma, beta, and alpha
• E. beta, alpha, and gamma

Answer 1

Answer: (D)

gamma, beta, and alpha

$\gamma$ rays are highly penetrating of the three types of rays , $\gamma$ rays are high energy photons of electromagnetic waves having extremely small wavelength i.e. high frequency.

$\beta$ rays are streams of electrons and are the swiftest material particles , due to high kinetic energy they have good penetration power but smaller than $\gamma$ rays.

$\alpha$ particles are massive particles due to this they have least penetration power of the three types of rays.

therefore , decreasing order of penetration is $\gamma ,\beta ,\alpha$.