- Home
- Standard 12
- Physics
13.Nuclei
medium
A radioactive substance has an average life of $5$ hours. In a time of $5$ hours
A
Half of the active nuclei decay
B
Less than half of the active nuclei decay
C
More than half of the active nuclei decay
D
All active nuclei decay
Solution
(c) If $\lambda $ is the decay constant of a radioactive substance than average life = $\frac{1}{\lambda }$
Also half life $ = \frac{{0.693}}{\lambda } = 0.693 \times (Average\;life)$
in single average life, more than $63\%$ of radioactive nuclei decay
Standard 12
Physics
Similar Questions
Match the nuclear processes given in column $I$ with the appropriate option$(s)$ in column $II$
| column $I$ | column $II$ |
| $(A.)$Nuclear fusion | $(P.)$ Absorption of thermal neutrons by ${ }_{92}^{213} U$ |
| $(B.)$Fission in a nuclear reactor | $(Q.)$ ${ }_{27}^{60} Co$ nucleus |
| $(C.)$ $\beta$-decay | $(R.)$ Energy production in stars via hydrogen conversion to helium |
| $(D.)$ $\gamma$-ray emission | $(S.)$ Heavy water |
| $(T.)$ Neutrino emission |
