Chapter V review
Answers are for parents and teachers.
1
The Earth’s equator is about 40 000 km long. How many times could light travel that distance in 1 s? (c = 300 000 km/s)
300 000/40 000 = 7.5 times
2
If the angle of incidence is 50°, what is the angle between incident and reflected rays at a plane mirror, in degrees?
100
3
At the substance–air boundary sin α₀ = 0.8. Find n and v (c = 3·10⁸).
n = 1.25; v = 2.4·10⁸ m/s
4
A lens has F = 8 cm and the object is at d = 12 cm. Find f and Γ.
f = 24 cm, Γ = 2
5
A magnifier has F = 5 cm. What is K and what image does it give?
K = 25/5 = 5; a virtual, upright, enlarged image.