# Electron & Cost Problems

1. Jan 13, 2004

### mustang

Problem4.
A total charge of 12mC passes througha cross-sectional area of a nichrome wire in 3.1s.
How many electrons pass through the cross-sectional area in 30.0s? In units of electrons.
Note: What formula should I use?

Assume electrical energy cost $0.080 per k*W*h, and that appliances have a potential difference across them of 113 V. Problem 16. Calculate the cost of running an electric oven that draws 26.0A of current for 24hr. In units of$.
Note: How do I do this problem.

Problem 17.
Calculate the cost of running a television with a resistance of 27 ohms for 24hr. In units of \$.

2. Jan 14, 2004

### fannemel

Problem 4:
An electron has charge, and it's charge is the smallest amount of charge possible. Thus all greater charges equals a whole number of those.

Formula would be:
Nq = 12mC

where N = number of electron and q = e the electron charge = 1.60 * 10^-19

then you can find how many electrons that pass in 3.1 seconds and when you know that it's easy to find out how many that passes in 30s.

For the other problems use formulas
P = VI (P=W in your formula)
U = RI

Last edited: Jan 14, 2004