Question

1500 W 128 W 822 W Fuse Figure 2: Picture of the setup in problem 5 4.) Which configuration of charge has more electric potential energy? (a.) an equilateral triangle (all sides the same length 1) with positive charge +g at each corner or (b.) a square (all sides have length 1) where three corners are occupied by +q charges and the final is occupied by charge -q? Show all work. (pun sort of intended "hint hint) 5.) A circuit is ftted with a fuse with a current threshold of 40A, will it blow (see Fig. 2)? Show all work.

Answer 1

4) The triangle configuration will have more electric potential energy. The reason is that it has all positive charges so all the terms are additive while for configuration (b) there will be 3 minus terms due to the presence of a negative charge.

5) We need to calculate the circuit current. If it is more than the threshold of 40A, the fuse will blow.

Determine the current in each of the 4 branches and add them.

We know P = VI

=> I = P/V

so:

I1 = 1500/60 = 25A

I2 = 20/60 = 0.33A

I3 = 128/60 = 2.13A

I4 = 822/60 = 13.7

Total current I = I1 + I2+ I3 +I4 = 41.16A

This is greater than the threshold of 40A. So the fuse will blow.