Question

the half life of a radioactive substance is 2mins. calculate the decay constant

Answer 1

Given :

▪ Half life of radioactive substance = 2min

To Find :

▪ Decay constant of radioactive substance.

Solution :

Half-life of a radioactive substance is given by

▪ T(1/2) = ln2/$\lambda$ = 0.693/$\lambda$

where,

T(1/2) denotes half life

$\lambda$ denotes decay constant

→ T(1/2) = 0.693/$\lambda$

→ $\lambda$ = 0.693/T(1/2)

→ $\lambda$ = 0.693/2

→ $\bf\lambda=0.346\:min^{-1}$

Extra Dose :

Mean life or average life of a radioactive substance is given by

▪ $\tau$ = 1/$\lambda$ = T(1/2)/0.693 = 1.44T(1/2)

Answer 2

Answer:

YOUR QUESTION :

The half life of a radioactive substance is 2mins. calculate the decay constant.

YOUR ANSWER :

Given :

• Half life of radioactive substance = 2min

To Find :

• Decay constant of radioactive substance.

Solution :

Half-life of a radioactive substance is given by

• T(1/2) = ln2/\lambdaλ = 0.693/\lambdaλ.

=> T(1/2) = 0.693/\lambdaλ

=> \lambdaλ = 0.693/T(1/2)

=> \lambdaλ = 0.693/2

=> \bf\lambda=0.346\:min^{-1}λ=

0.346min^-1