Physics Past Questions and Answers

Cancerous cells can be destroyed by

If the decay constant of a radioactive substance is 0.231s¹, the half-life is?

A piece of radioactive material contains 10²⁰ atoms.
If the half life of the material is 20 seconds, the number of disintegration in the first second is

Thermionic emission is the process whereby

Which of the following can conduct electricity owing to the presence of free mobile electrons?