Unit 10 Problems

CC2404 Applied Physics and Instrumentation in Health Care Problems Unit 10 (2009)

1. The electromagnetic spectrum includes radio waves, microwaves, infra-red, visible light, ultraviolet, X-rays and gamma rays. a Which statement about electromagnetic waves is correct? A They all have the same wavelength. B They all have the same frequency. C They are all transverse waves. b Name two types of electromagnetic wave used to cook food. c Name one type of electromagnetic wave used to detect a break in a bone. (London Foundation, June 99) 2. Which of the following types of radiation has a the longest wavelength, b the highest frequency A UV B radio waves C light D X-rays E IR 3. Name one type of electromagnetic radiation which a causes sun-tan, b is used for satellite communication, c is used to sterilize surgical instruments d is used in TV remote control 4. Which of the following is NOT a factor that would affect the amount of UV radiation reaching the ground? a. b. c. d.

Latitude Altitude Longitude Sun elevation

5. What is the possible long-term hazard of UV on human skin? a. induction of skin cancer b. reddening of the skin c. Vitamin D 6. Which of the statement concerning the causes of suntan and sunburn is correct? a. b. c. d.

UV-A causes suntan and UV-B causes sunburn UV-A causes sunburn and UV-C causes suntan Both UV-A and UV-B will cause suntan but not sunburn Both UV-A and UV-B will cause sunburn but not suntan

7. Decide each of the following statement true or false. a) A tan results from your body defending itself against further damage from UV radiation. You can’t get sunburnt on a cloudy day. b) You can’t get sunburnt while in the water. c) UV radiation exposure is cumulative during the day.

8. A VHF radio station transmits on a frequency of 100 MHz (1 MHz = 106 Hz). If the speed of radio waves is 3× 108m/s, a what is the wavelength of the waves, b how long does the transmission take to travel 60km? c. What is its photon energy in J and in eV ?