Intensity and polarisation Quiz
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5 questions, one answer each
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1. A point source of power 20 W radiates uniformly. What is the intensity at 1.0 m?
- A. 6.4 W m⁻²
- B. 0.16 W m⁻²
- C. 1.6 W m⁻²
- D. 20 W m⁻²
2. The intensity from a point source is 36 W m⁻² at 2.0 m. What is it at 6.0 m?
- A. 4.0 W m⁻²
- B. 12 W m⁻²
- C. 18 W m⁻²
- D. 6.0 W m⁻²
3. Which wave cannot be plane polarised?
- A. Light
- B. Microwaves
- C. Radio waves
- D. Sound
4. A solar panel of area 2.0 m² receives sunlight of intensity 800 W m⁻² and has an efficiency of 20%. What is its electrical output?
- A. 1600 W
- B. 320 W
- C. 80 W
- D. 3200 W
5. A student rotates one polarising filter in front of another, both in front of a lamp. What does she see when the transmission axes are perpendicular?
- A. Maximum brightness
- B. Half brightness
- C. Almost no light
- D. Brightness that depends on the colour of the lamp