Question

the most difficult radiation to block out is
a. alpha particles
b. gamma rays
c. beta particles
d. neutron
the spontaneous emission of radiation by a nucleus is know

Explanation:

Gamma rays are highly - energetic electromagnetic radiation. They have the highest penetrating power among common types of radiation. Alpha particles can be stopped by a sheet of paper, beta particles by a few millimeters of aluminum, but gamma rays require thick layers of dense materials like lead or concrete to block.

Answer:

b. gamma rays