Electromagnetic Spectrum Questions and Answers - Physics Form 4 Topical Revision

Questions

1. State one-way of detecting ultra violet radiation.
2. Arrange the following radiations in order of increasing wavelengths.
   Ultraviolet        Gamma Rays
   Radio Waves     Infra Red
3. Name two types of electromagnetic radiations whose frequencies are greater than that of visible light.
4. Calculate the wavelength of the KBC FM radio waves transmitted at a frequency of 95.6 mega hertz.
5. The chart below shows an arrangement of different parts of the electromagnetic spectrum. Complete the table.
   

   Type of Radiation	Detector	Uses
   Ultraviolet	Photographic paper, fluorescent material, phototransistor
   Radio waves	Balanced thermometer	Warmth sensation, making toast
   Radio waves		Communication

6. Arrange the following in order of increasing frequency. Visible light, infrared radiation, x-rays, u.v. radiation, radio waves.
7. State the difference between X-rays and gamma rays in the way in which they are produced (1mk)
8. Other than a photographic film state one other detectors of
   1. X-rays
   2. UV,
   3. Visible spectrum
   4. Infra-red radiations
9. State 3 uses of infra- red radiation.
10. Name two properties of ultra-violent radiation.
11. State the origin of all em-radiation from radio waves to x-rays.
12. State where Gamma rays originate.
13. State one common property for electromagnetic waves and state one use of microwaves and one for ultraviolet radiation.
14. State one common properties for electromagnetic waves and state one use of microwaves and one for ultraviolet radiation.
15. Name the radiation represented by A.
    Radio, Infrared, visible, A- rays, Gamma Rays 
16. Complete the table below to show the name and use of some types of electromagnetic radiation.
    

    Type of radiation	Use
    	Sendng Information to and from satellites
    	Normal Photography
    	Producing shadow pictures of bones
    Gamma rays

17. Give one important use of each of the following em-waves.
    1. Microwaves
    2. Infrared

Answers

1. Using a photocell/a fluorescent screen; photographic plate; also paper smeared with Vaseline or quinine sulphur.
2. Gamma rays, Ultraviolet, Infrared, Radio waves.
3. Ultra violets rays, X-rays, Gamma rays.
4. v = f x wavelength.
   = v = 3.0 x 10ms^-1
       f    95.6 x 106s^-1
   = 3.14 m
5.  
   1. Killing germs, vitamin D synthesis, fluorescent lamps/screen/signboard, vehicle reflectors, paints etc.
   2. Infrared radiation.
   3. Radio receiver.
6. Radio waves, Infrared, Visible light, U-V radiation, X-rays.
7. X-rays are produced from changes in energy from electron jumps in the shells of an atom while gamma rays are produced from energy changes in the nucleus of atoms.
8.  
   1. Scintillation tube, Geiger muller tube etc.
   2. Fluorescent materials, paper smeared with Vaseline etc.
   3. Eye, photometer.
   4. Skin, blackened thermometer etc.
9. Warmth sensation, cooking, drying clothes etc.
10. - They cause fluorescent.
    - They all travel at 3 x 10^-8m/s.
    - They are part of em-spectrum and can travel through vacuum.
    - Transverse
11. Electron jumps/ energy changes in electron structure of atoms.
12. Energy changes in the nucleus of atoms.
13. - They all travel at 3 x 10^-8m/s.
    - All transverse.
    - Can be plane polarized.
    - They can travel through vacuum.
14.  
    1. Radio waves, infrared, visible light, U-V radiation, X-rays.
    2. Microwaves are used in cooking.
    3. Ultraviolet are used in fluorescent paints.
15. X-rays.
16.  
    1. Radio waves
    2. Visible light.
    3. X-rays
    4. Treatment of cancer (radio therapy), detection of fault in manufacturing industry, sterilization/killing germs.
17.  
    1. Cooking
    2. Drying objects.