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Unit 20: Electromagnetic Waves

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1. Which color has the highest frequency in visible light?

A Red

B Green

C Blue

D Violet

2. Which electromagnetic wave is used in photography?

A Radio waves

B Visible light

C X-rays

D Gamma rays

3. Which wave property determines the color of light?

A Amplitude

B Frequency

C Speed

D Intensity

4. Microwaves are commonly used for

A Cooking food

B Medical imaging

C Sterilization

D Photography

5. Which electromagnetic waves are used in TV and radio broadcasting?

A Infrared waves

B Radio waves

C X-rays

D Ultraviolet rays

6. Which electromagnetic waves are used in satellite communication?

A Ultraviolet rays

B Microwaves

C X-rays

D Gamma rays

7. X-rays are mainly used for

A Cooking

B Communication

C Medical diagnosis

D Heating

8. Scattering of light explains why the sky appears

A Red

B Blue

C Green

D Yellow

9. Light travels in straight lines in a medium due to

A Reflection

B Rectilinear propagation

C Diffraction

D Interference

10. Overexposure to ultraviolet radiation may cause

A Skin cancer

B Hearing loss

C Muscle pain

D Heart disease

11. Electromagnetic waves consist of oscillating

A Electric and magnetic fields

B Electric charges only

C Magnetic poles only

D Particles only

12. Which color has the longest wavelength in visible light?

A Blue

B Green

C Yellow

D Red

13. Which scattering is responsible for the blue color of the sky?

A Mie scattering

B Rayleigh scattering

C Compton scattering

D Photoelectric scattering

14. The speed of electromagnetic waves in vacuum is

A 3 × 10^6 m/s

B 3 × 10^7 m/s

C 3 × 10^8 m/s

D 3 × 10^9 m/s

15. Which electromagnetic wave is safest for human exposure?

A Gamma rays

B X-rays

C Ultraviolet rays

D Radio waves

16. Which color of light is scattered the most in the atmosphere?

A Red

B Yellow

C Blue

D Orange

17. Which electromagnetic waves are used in night vision devices?

A Ultraviolet rays

B X-rays

C Infrared rays

D Gamma rays

18. Which factor increases the risk of electromagnetic radiation?

A Low frequency

B Short wavelength

C Low energy

D Long wavelength

19. Visible light lies between which two regions of the electromagnetic spectrum?

A Infrared and ultraviolet

B Microwaves and infrared

C X-rays and gamma rays

D Radio waves and microwaves

20. Why clouds appear white?

A Due to absorption

B Due to reflection of blue light

C Due to scattering of all wavelengths

D Due to refraction

Unit 20: Electromagnetic Waves

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