PREVIOUSLY ASKED IN:
WBPSC Miscellaneous Preliminary 2019
Answer
Becquerel
Explanation
The SI unit of radioactivity is the 'Becquerel' (Bq). It is named after the physicist Henri Becquerel, who discovered radioactivity. One Becquerel is defined as one radioactive decay or disintegration per second. Curie (Ci) and Rutherford (Rd) are also units of radioactivity, but they are traditional, non-SI units.
Key Points
- > Radioactivity was discovered by Henri Becquerel in 1896.
- > Curie (Ci) is a non-SI unit of radioactivity. (1 Ci = 3.7 × 10^10 Bq).
- > The Geiger-Muller Counter is an instrument used for measuring ionizing radiation.
- > Ampere is the SI unit of electric current.
- > Volt is the SI unit of electrical potential difference.
Additional Information
Physical Quantities & SI Units
| Physical Quantity | SI Unit | Symbol |
|---|---|---|
| Radioactivity | Becquerel | Bq |
| Electric Current | Ampere | A |
| Potential Difference | Volt | V |
| Resistance | Ohm | Ω |
| Frequency | Hertz | Hz |
Memory Tips
- Radioactivity: Named directly after its discoverer Henri Becquerel.
- Curie vs Becquerel: Remember that Becquerel is the modern SI standard, whereas Curie is an older, much larger unit.