Quiz 7b (Phys 101 - 11.30am, Spring 2005)

Name: __________________Answers____________________

1. (a) For reflection from a surface, if the angle of incidence is equal to the critical angle what can you say about the refracted beam?

The refracted beam is traveling along the surface.

(b) If the angle of incidence is greater than the critical angle what can you say about the refracted beam?

There is no refracted beam i.e. all the light is reflected from the surface.

2.

a) In the circuit above what is the current I flowing through the circuit?

R = R₁ + R₂ = 10 + 10 = 20W for a series circuit.

I = V/R = 20/20 = 1A

b) If the electricity is left on for a time of 10s, how much electrical energy is converted to light (and heat)?

EPE = IVt = 1x20x10 = 200J