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.
 
 

Final answer: ____________.
 

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.
 
 

Final answer: ____________.
 

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.
 
 

Final answer: ____________.

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.
 
 

Final answer: ____________.
 
 


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