Question

Consider the table below that summarizes the types of materials that can block the 3 different types of radiation.

Material
1
2
3
Lead Stopped Stopped Stopped
Cloth Not stopped Stopped Stopped
Aluminum foil Not stopped Stopped Stopped
Wood Not stopped Stopped Stopped
Paper Not stopped Stopped Not stopped
Thick concrete Stopped Stopped Stopped

Based on the table, at which numbered spot in the table does each type of radiation belong?

1 = beta; 2 = gamma, 3 = alpha
1 = gamma; 2 = alpha, 3 = beta

Answer 1

1 = gamma; 2 = alpha; 3 = beta.

Reason: paper stops the radiation in column 2 (alpha is stopped by paper/clothing), aluminum foil stops column 3 but paper does not (beta is stopped by thin metal but not paper), and only heavy shields (lead, thick concrete) stop column 1 (gamma is the most penetrating).