Solar energy is due to:
1. | fusion reaction. | 2. | fission reaction. |
3. | combustion reaction. | 4. | chemical reaction. |
At time t = 0, N1 nuclei of decay constant λ1 and N2 nuclei of decay constant λ2 are mixed. The decay rate of the mixture is:
1.
2.
3.
4.
The half-life period of a radioactive substance is 6 h. If after 24 h, activity is 0.01 Ci, what was the initial activity?
1. 0.04 Ci
2. 0.08 Ci
3. 0.24 Ci
4. 0.16 Ci
Which of the following is used as a moderator in nuclear reactors?
1. Plutonium
2. Cadmium
3. Heavy water
4. Uranium
1. | \({}_{7}^{13}\mathrm{N}\) | 2. | \({}_{5}^{10}\mathrm{B}\) |
3. | \({}_{4}^{9}\mathrm{Be}\) | 4. | \({}_{7}^{14}\mathrm{N}\) |