Electricity Problems Review
Formulas: V = IR (or R = V/I) and P = IV

1) If your toaster draws 5 A of 120 V current, what is its resistance?

What are the following variables worth?  (Put a question mark by the variable the problem is asking for.  If a variable is not mentioned, scratch it out.)
I = ________R = ________
V = ________P = ________

Which equation should you use?

How should it be rearranged (if at all) to solve for the unknown?

“Plug in” the values and solve it.

2) What is the voltage of across a 75 Ohm resistor with 10 A of current?

What are the following variables worth?  (Put a question mark by the variable the problem is asking for.  If a variable is not mentioned, scratch it out.)
I = ________R = ________
V = ________P = ________

Which equation should you use?

How should it be rearranged (if at all) to solve for the unknown?

“Plug in” the values and solve it.

3) If your toaster draws 5 A of 120 V current, what is its power?

What are the following variables worth?  (Put a question mark by the variable the problem is asking for.  If a variable is not mentioned, scratch it out.)
I = ________R = ________
V = ________P = ________

Which equation should you use?

How should it be rearranged (if at all) to solve for the unknown?

“Plug in” the values and solve it.

4) What current is drawn by a 9 V battery producing 2 W of power?

What are the following variables worth?  (Put a question mark by the variable the problem is asking for.  If a variable is not mentioned, scratch it out.)
I = ________R = ________
V = ________P = ________

Which equation should you use?

How should it be rearranged (if at all) to solve for the unknown?

“Plug in” the values and solve it.