Physics 2nd Paper MCQ-Dinajpur Board-2023

1. The half-life of a radioactive substance is 1.2 day. After 4.8 days how many portions of that radioactive substance will decay?

2. Which of the following is a unit of rate of charge flow?

3. $\mathrm{P} \xrightarrow{\alpha} \mathrm{Q} \xrightarrow{\gamma} \mathrm{R} \xrightarrow{\beta} \mathrm{S}$

Here, $\alpha, \gamma$ and $\beta$ means the emitted radioactive radiation from $\mathrm{P}, \mathrm{Q}$ and $\mathrm{R}$ respectively. $\mathrm{Z}$ is the atomic no. of $P$.

The atomic no. of substance ' $S$ ' will be-

4. The unit of Mechanical Equivalent of heat is-

5. Which of the following reactions produces energy in a nuclear reactor?