Prove rthat the instantaneous rate of change of the activity of a radioactive substance is inversely propoertional to the square of its half-life.

Define half life of a radioactive substance.

Distinguish between half and average life of a radioactive substance.

A radioactive substance decays to 1//32 th initial activity in 25 days.Calculate its half life.

What is meant by half life of a radioactive substance? Derive expression for them. What is relation between average life and half life?

If the activity of a radiacctive element drops to frac(1)(16)th of its inital value in 40 years. Find its half-life period.

Read the given passage and answer the questions A substance which alters the rate of chemical reaction without undergoing any change in mass and chemical composition at the end of reaction is called catalyst. It may be noted that catalyst which increases the speed of a reaction is called positive catalyst and catalyst which decrease the speed of reaction is called negative catalyst. The promoters are substances that enhance the activity of catalyst and poisons are the substances which decrease the activity of catalyts. What are poisons ?