1. A laser beam has a velocity in vacuum of c = 3 x 108 m/s. A student runs an experiment in which a liquid is placed in a tank of length L = 14.1 m. The time it takes for the beam to make it across the tank is timed to be t = 65 ns. Write an expression for the liquid's index of refraction, n. Numerically, what is this index?
2. An automobile starter motor has an equivalent resistance of 0.025 Ω and is supplied by a 12.0 V battery which has a 0.025 Ω internal resistance. What is the current to the motor in A? What voltage is applied to it in V? What power is supplied to the motor in kW?