Question

The half life of a radio active substance is 13 years then the decay constant us

Answer 1

Answer:

Half life time of a substance is ln2/decay constant so that decay constant = 0.6909/13 = 0.053

Answer 2

Solution :

Given :-

The half life of a radio active substance is 13 years.

To Find :-

Decay constant of radio active substance.

Formula :-

▪ Half life of a radioactive substance is given by

$\boxed{\bf{\pink{T_{1/2}=\dfrac{ln(2)}{\lambda}=\dfrac{0.693}{\lambda}}}}$

Calculation :-

$\implies\sf\:\lambda=\dfrac{0 693}{T_{1/2}}\\ \\ \implies\sf\:\lambda=\dfrac{0.693}{13}\\ \\ \implies\underline{\boxed{\bf{\purple{\lambda=0.053\:(year)^{-1}}}}}$

Additional information :-

• The radioactive radiations are of three types, α-rays, β-rays and r-rays.
• An α-particle carries two units of positive charge and four units of mass.
• A β-particle carries unit negative charge and has negligible mass.