Plutonium-238 (Pu-238\text{Pu-238}Pu-238) is a radioactive element.
This is the symbol for Pu-238\text{Pu-238}Pu-238:
94238Pu^{238}_{94}\text{Pu}94238Pu
Match each property of this nucleus with its correct numerical value.
- Properties: Mass number, Number of protons, Number of neutrons
- Values: 94, 144, 238
A physicist measures the background-corrected counts per minute (cpm) of a sample of Pu-238\text{Pu-238}Pu-238 five different times.
Table 1 shows their results:
| Measurement | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|
| Count rate (cpm) | 425 | 418 | 425 | 431 | 422 |
What is the mode of the count rate measurements?
Mode = ............................................................ cpm
An alpha particle is emitted by Pu-238\text{Pu-238}Pu-238. Complete the radioactive decay equation for this decay:
94238Pu→……234U+2……He^{238}_{94}\text{Pu} \rightarrow ^{234}_{\dots\dots}\text{U} + ^{\dots\dots}_{2}\text{He}94238Pu→……234U+2……He
A student says, 'Beta radiation is more dangerous than alpha radiation.'
Do you agree with this student? Explain your answer with reference to ionising and penetrating power.
A laboratory technician is using a radioactive element. They accidentally inhale some radioactive dust containing Pu-238\text{Pu-238}Pu-238 and become contaminated.
The technician immediately washes their skin and leaves the laboratory.
Explain why the technician is still at risk.
Pu-238\text{Pu-238}Pu-238 is commonly used to generate heat in radioisotope thermoelectric generators (RTGs). The thermal power output generated increases linearly with the mass of Pu-238\text{Pu-238}Pu-238.
This is a graph of thermal power output against mass of Pu-238\text{Pu-238}Pu-238:
Use the graph to find the mass of Pu-238\text{Pu-238}Pu-238 needed for a thermal power output of 0.28 kW.
Mass = ............................................................ kg
Plutonium-238 is used to power spacecraft on deep-space exploration missions (such as the Voyager probes). The half-life of Pu-238 is 87.7 years.
Suggest why Pu-238 is suitable for powering probes on long-duration space missions.