Question

A scientist has two radioactive substances. One emits beta particles, and the other emits alpha particles. He thinks that since the alpha particles are larger, they are more dangerous to humans. What is wrong with his reasoning?

Answer 1

Alpha particles cannot penetrate skin, it is too large to do so. Beta particles can penetrate skin and cause more disturbance

Answer 2

As we know that the penetration of the particles depends on the energy of the particles that they have in it.

Now if the particles penetrate more then it will have more energy in it

So we can say that out of all radioactive particles maximum penetration is for gamma rays and least penetration is for alpha particles.

So here maximum energy is for gamma rays and minimum energy is for alpha particles.

So size is not the criteria to decide the energy of the particles but the penetration capacity is the right criteria to decide this.

So out of alpha and beta particles the beta particles are more dangerous than alpha particles.