Activity is the number of 7.65 μJ decays that happen in a Calculate the activity of a second. source using the G-M tube, stop watch and the Radioactivity decay is when counter. an unstable atom emits a Repeat this until the radioactive particle and a activity is halved. becomes a different Check how long has element. passed with the clock. This is the half life. 3.5 Bq 15 minutes 60 000 B 450 s Gamma can penetrate tissue. Connect the G-M tube to The half-life is a the counter. reasonable value to be Move it close to the useful and safe. radioactive source. Measure how many counts are in 30 seconds. Calculate activity using A = N/ t. 6.5 Bq 30 Bq Half Life (p20 – 21) Absorbed Dose (p22) Equivalent Dose (p23 – 25) Activity decreases. Absorbed does is the Equivalent dose is a amount of energy measure of the biological Half life is the time taken absorbed from a harm of exposure to a for the activity of a radiation by a kilogram of radiation. radioactive source to a material. reach half of its original (a) 4.2 μSv value. (a) 2 x 10-5 Gy 5.1 x 10-5 Sv 1.4 x 10-4 Gy 6.8 μGy 25 kBq 4.4 μJ 1.75 μGy 16.9 μJ 10 3 years 0.3 kg 3 0.15 kg 960 Bq 4.5 μSv 17.5 μGy 9pm on Thursday 0.4 mSv 0.42 kg 9 months (a) 20
Activity is the number of decays that happen in a second. Radioactivity decay is when an unstable atom emits a radioactive particle and a becomes a different element. 3.5 Bq 60 000 450 s Connect the G-M tube to the counter. Move it close to the radioactive source. Measure how many counts are in 30 seconds. Calculate activity using A = N/ t. 6.5 Bq 30 Bq Half Life (p20 – 21) Activity decreases. Half life is the time taken for the activity of a radioactive source to reach half of its original value. 25 kBq 3 years 960 Bq 9pm on Thursday 9 months Calculate the activity of a source using the G-M tube, stop watch and the counter. Repeat this until the activity is halved. Check how long has passed with the clock. This is the half life. 15 minutes B Gamma can penetrate tissue. The half-life is a reasonable value to be useful and safe. Absorbed Dose (p22) Absorbed does is the amount of energy absorbed from a radiation by a kilogram of a material. (a) 2 x 10-5 Gy 1.4 x 10-4 Gy 4.4 μJ 16.9 μJ 0.3 kg 0.15 kg 17.5 μGy 0.42 kg 7.65 μJ Equivalent Dose (p23 – 25) Equivalent dose is a measure of the biological harm of exposure to a radiation. (a) 4.2 μSv 5.1 x 10-5 Sv 6.8 μGy 1.75 μGy 10 3 4.5 μSv 0.4 mSv (a) 20
Waves-and-Radiation-Problem-Booklet-27he174.docx