What different kinds of radiation do when absorbed

Answer Key - Grade 11 Science Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   A microwave oven rated 800 W runs for 30 s, and 0.25 kg of water absorbs all of it. With c = 4182 J/(kg·°C), how much does the water warm, to 0.1 °C, Ari?

   23 °C
2. 2.

   A microwave oven rated 1000 W runs for 60 s, and 0.5 kg of water absorbs all of it. With c = 4182 J/(kg·°C), how much does the water warm, to 0.1 °C, Bo?

   28.7 °C
3. 3.

   A microwave oven rated 700 W runs for 45 s, and 0.3 kg of water absorbs all of it. With c = 4182 J/(kg·°C), how much does the water warm, to 0.1 °C, Esme?

   25.1 °C

4. Read this first

   Energy carried by one photon (worked out with E = hf)

   Band	Frequency (Hz)	Energy per photon (eV)
   FM radio	100,000,000	0.00000041
   green light	600,000,000,000,000	2.48
   ultraviolet	1,500,000,000,000,000	6.2
   X-ray	3,000,000,000,000,000,000	12,407

5. 4.

   Using the table, which photon carries the most energy, Jun?

   • The FM radio photon
   • The X-ray photon
   • The green light photon
6. 5.

   Using the table, about how many times the energy of a green-light photon does the ultraviolet photon carry, Kira?

   • About 25 times
   • About the same
   • About 2.5 times
7. 6.

   A radio tower sends out a very powerful signal. Does that make its radio waves ionizing, Milo?

   • Yes: a powerful enough beam ionizes
   • No: each photon has too little energy
   • Yes: radio waves are ionizing
8. 7.

   A very dim X-ray beam and a very bright lamp shine on a sheet. Which can ionize atoms in it, Noah?

   • Neither of them
   • The bright lamp, since it is brighter
   • The dim X-ray beam
9. 8.

   A green laser pointer is turned brighter. What changes about its photons, Pia?

   • More arrive each second
   • They change into ultraviolet
   • Each one carries more energy
10. 9.

    Where does most people's yearly radiation dose of about 3 mSv come from, according to RadiologyInfo, Tala?

    • Natural background sources
    • Microwave ovens
    • Radio broadcasts and phone towers
11. 10.

    X-ray imaging doses are small. Why are they still kept as low as possible, Zee?

    • X-rays are slower than light
    • The dose is kept to what is needed
    • X-ray machines warm the whole room