Question

1. A wire W1 of some resistance is connected to a batter with potential V, and...

1. A wire W1 of some resistance is connected to a batter with potential V, and dissipates a power P1. A second wire W2, twice as long as W1, is connected to the same battery, and dissipates a power P2 = 2P1. From this we can conclude:

a) The wires must be made of the same material.

b) The wires must have the same cross-sectional area.

c) The resistance of W1 must be less than that of W2.

2. Two spheres, one with a charge of -Q and the other with a charge of +2Q are separated by a distance R, and exert a force F on each other. The spheres are now altered so that the force between them is 2F. Which of the following would have produced this result?

a) The charge on both spheres was doubled

b) The charge on only one sphere was increased by a factor of 4.

c) The charge on both spheres was doubled, and the distance between them halved.

d) The charge on only one sphere was halved, and the distance between them halved.

e) The charge on both spheres was increased by a factor of 4, and distance between them doubled.