Question

In last week's written HW you used a voltage to generate motion in a sliding metal rail

that slid along two wires on the ground. This week you'll consider the opposite case, moving

the rail to generate a voltage and power a lightbulb. Again the rail is free to move along the

wires without any friction. The fixed wires are now 1 m apart and at t = 0 the rail is 2 m

from the bulb.

This circuit will take advantage of the Earth's magnetic eld. In Boulder, this has a

magnitude of 5010?6 T and is directed downward at an angle of 66 with respect to the

ground, as shown below.

a.) At time t=0, what is the magnetic flux through the wire+rail loop?

b.) Suppose you decide to pull along the sliding metal rail behind you while jogging to the

right at a speed of 10 km per hour (so that you are increasing the area of the loop).

What is the voltage induced in the loop?

c.) For a flashlight bulb that normally operates with a 1.5 V battery, do you think that

your jogging with the rail will make it glow very brightly? What could you do to

increase the voltage generated? Does this seem like a very practical way of powering

something?

d.) Please sketch the direction of the induced current in the (first) Top View the diagram

on the previous page. Clearly explain how you can tell the direction.

Answer 1