Intensity and refraction Quiz
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5 questions, one answer each
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1. A detector of area 0.50 m² receives 20 W of radiation at right angles. What is the intensity?
- A. 0.025 W m⁻²
- B. 10 W m⁻²
- C. 40 W m⁻²
- D. 20 W
2. The speed of light in a liquid is 2.25 × 10⁸ m s⁻¹. What is its refractive index?
- A. 1.33
- B. 0.75
- C. 1.50
- D. 6.75 × 10⁸
3. Light in air hits water (n = 1.33) at an angle of incidence of 45°. What is the angle of refraction?
- A. 45°
- B. 60°
- C. 28°
- D. 32°
4. A ray passes from glass into air. Which statement is correct?
- A. It speeds up and bends towards the normal
- B. It speeds up and bends away from the normal
- C. It slows down and bends away from the normal
- D. It slows down and bends towards the normal
5. A student plots sin i against sin r for light entering a block from air and finds a gradient of 1.60. What does this show?
- A. The block has a refractive index of 0.63
- B. The speed of light in the block is 1.60 × 10⁸ m s⁻¹
- C. The block has a refractive index of 1.60
- D. The critical angle is 1.60°