The binding energy is the energy required to separate a nucleus into its individual protons and neutrons.
ClosePenetrating power can be thought of as the distance it can travel through a material before it is stopped. Gamma particles are very hard to stop, as they have a large penetrating power. This is why gamma particles are much more dangerous than alpha particles.
CloseRadioactive decay is random because we cannot predict when, and which nucleus will decay.
CloseIf we measured 100 counts per minute and the background is 20, that means our sample emits 80 counts per minute. This will halve 2 times in the span of 4 minutes, leaving 20 counts per minute. Adding the background radiation, we get 40 counts per minute.
CloseThe activity is the product of the decay constant and the number of particles, so if we double the number of particles, the activity also doubles. The half-life cannot change as it is a constant for an isotope.
CloseRadioactive decay is spontaneous, meaning nothing can be done to alter the speed of decay.
CloseIt can be observed that it has halved in mass 3 times, in a period of 60 minutes, hence the half-life is 20min.
CloseThe correct answer is: B.
Binding energy per nucleon increases up to a maximum value near \( A = 56 \) (iron group), indicating the most stable nuclei, and then decreases for larger nucleon numbers due to the reduced effect of the strong nuclear force relative to the Coulomb repulsion.
CloseThe correct answer is: A.
The activity after \( t \) time is given by: \[ A_t = A_0 \left( \frac{1}{2} \right)^{\frac{t}{T}} \] where \( A_0 = 800 \: \mathrm{Bq} \), \( T = 6 \: \mathrm{hours} \), and \( t = 24 \: \mathrm{hours} \). Substituting: \[ A_t = 800 \left( \frac{1}{2} \right)^{4} = 800 \times \frac{1}{16} = 50 \: \mathrm{Bq} \]
CloseThe correct answer is: A.
Alpha particles are heavy and slow-moving, leading to low penetration ability (stopped by paper) but high ionizing power. Beta particles have moderate penetration ability (stopped by aluminum) and moderate ionizing power. Gamma rays have very high penetration ability (requires thick lead) but low ionizing power.
CloseThe correct answer is: A.
The binding energy is given by: \[ E = \Delta m c^2 \] where \( \Delta m = 0.002 \: \mathrm{u} \), \( 1 \: \mathrm{u} = 931.5 \: \mathrm{MeV/c^2} \). Substituting: \[ E = (0.002)(931.5) = 1.863 \: \mathrm{MeV} \]
CloseThe correct answer is: B.
The strong nuclear force is attractive at short ranges (approximately \( 10^{-15} \: \mathrm{m} \)) and negligible beyond this range. It acts between all nucleons (protons and neutrons) to bind the nucleus together.
CloseThe correct answer is: A .
Alpha decay reduces the nucleon number by 4 (2 protons and 2 neutrons). Beta decay converts a neutron into a proton or vice versa, changing the proton number but not the nucleon number. Gamma decay involves energy release without changing the composition of the nucleus.
CloseThe correct answer is: B.
The activity after \( t \) time is given by: \[ A_t = A_0 \left( \frac{1}{2} \right)^{t/T} \] where \( A_0 = 1600 \: \mathrm{Bq} \), \( T = 8 \: \mathrm{hours} \), and \( t = 32 \: \mathrm{hours} \). Substituting: \[ A_t = 1600 \left( \frac{1}{2} \right)^{32/8} = 1600 \left( \frac{1}{2} \right)^4 = 1600 \times \frac{1}{16} = 100 \: \mathrm{Bq} \]
Close| Option | Explanation |
|---|---|
| A | Binding energy per nucleon decreases uniformly with increasing nucleon number. |
| B | Binding energy per nucleon reaches a maximum at intermediate nucleon numbers. |
| C | Binding energy per nucleon increases continuously with nucleon number. |
| D | Binding energy per nucleon remains constant for all nucleon numbers. |
| Option | Activity (\( \mathrm{Bq} \)) |
|---|---|
| A | 50 |
| B | 100 |
| C | 200 |
| D | 400 |
| Option | Radiation Type | Penetration Ability and Ionizing Power |
|---|---|---|
| A | Alpha | Low penetration, high ionizing power |
| B | Beta | High penetration, high ionizing power |
| C | Gamma | High penetration, low ionizing power |
| D | Alpha | High penetration, low ionizing power |
| Option | Binding Energy (\( \mathrm{MeV} \)) |
|---|---|
| A | 1.86 |
| B | 4.82 |
| C | 18.64 |
| D | 32.46 |
| Option | Description |
|---|---|
| A | It is repulsive at short distances and attractive at larger distances. |
| B | It is attractive at short distances but negligible at larger distances. |
| C | It acts only between protons in the nucleus. |
| D | It is always repulsive. |
| Option | Description |
|---|---|
| A | Alpha decay decreases both the proton and neutron number by 2. |
| B | Beta decay increases the neutron number by 1. |
| C | Gamma decay changes the proton number. |
| D | Alpha decay increases the neutron number by 1. |
| Option | Activity (\( \mathrm{Bq} \)) |
|---|---|
| A | 50 |
| B | 100 |
| C | 200 |
| D | 400 |