Source: © Emond Montgomery Publications Limited
Mixed Electricity Problems
DON’T FORGET TO CHANGE TO THE STANDARD UNITS FIRST!
THERE ARE ONE AND TWO STEP QUESTIONS.
ANSWER ALL QUESTIONS ON A SEPARATE PAGE.
SHOW ALL OF YOUR WORK USING THE GRASS METHOD.
1. If a generator produces 120 V with a charge of 600 C, how much energy does it
produce?
2. A portable CD player needs only 2.5 mA of current. If the CD player is powered by a
9 V battery what is the resistance in the current?
3. A clothes dryer in your home is attached to a 220 V source. The heating elements
have a 12 Ω. What is the current in the heating coils of the dryer?
4. What is the resistance (in Ω) of a 1500 W dryer plugged into a 110 V outlet, if the
dryer has a 10 A current flowing through it?
5. How many Coulombs of charge pass through a 95 W amplifier plugged into a 110 V
wall socket over the course of a 2 hour concert?
6. A bulb plugged into a 110 V wall socket has a resistance of 100 Ω. Calculate how
many seconds it takes to pass 2000 C of charge.
7. 2500 Coulombs of charge is passed over a 2 hour period across a certain capacitor.
What is the resistance of this capacitor if the voltage across it is 200 mV?
8. What is the power of a microchip that passes 1 C of charge with a potential
difference of 0.01 mV in 1 second?
9. A simple circuit has a 9V battery attached to it. How long does it take to pass 1C of
charge through that battery if its resistance is 150 Ω?
10. What is the current in an electric stove element that creates 150 J of heat at 240 V
over a 5 minute period?
11. Write your own word problem that uses at least two of the equations. Then solve it!