Explain why a smoke alarm works by emitting and detecting alpha radiation instead of gamma or beta radiation.
Alpha radiation isn't very penetrating and so is absorbed and stopped by smoke particles. This causes a change in count rate when there is smoke present. This change in count rate allows the alarm to be triggered.Beta and gamma radiation aren't stopped by smoke particles and so there would be no change of count rate when smoke is present.
FM
Related Physics GCSE answers
All answers ▸A coil is connected to a voltmeter. A bar magnet, initially held above the coil, is left to fall into the coil. Explain why the voltmeter shows a reading. How will the reading of the voltmeter be affected if the magnet is dropped from a greater height?
Explain Ohms Law
An airplane accelerates steadily from rest to 355 m/s, after travelling a distance of 105,000 m. How long, in minutes, does it take the airplane to reach this speed?
What is red shift?