1. The starter in an automobile takes 4.0 s to start the engine. The current the starter draws is
225 A. Calculate the charge that passes through the starter.
2. The current drawn by an electric motor is 0.40 A. If 8.0 C of charge flow through the motor,
how long was the motor operated for?
3. The current flowing through a light bulb is 0.50 A. Calculate the number of electrons passing
through the bulb per second.
4. An electrical current is flowing for 15 min. Determine the quantity of charge that is transferred
by the current.
5. Calculate how long it takes to transfer a charge of 15 C by a current of 7.5 mA.
6. The electric potential that operates a stove is 120 V. How much energy does the stove use
given that the charge transferred through the element is 800 C?
7. An electric heater operates with an electric potential of 240 V. The heater draws a current of
6.0 A. If you only want to use 2.2 X 105 J of energy, how long can you operate the heater?
8. An electron is accelerated through a potential difference of 1.0 MV. What is its energy?
9. The energy that flows through a lawn mower in 45 s is 10 800 J. The current the mower
draws is 2.0 A. Calculate the potential difference across the mower.
10. A microwave oven uses 34 200 J of energy during a 30 s use. If the potential difference it
operates at is 120 V, what is the current through the oven?
11. The work done by an electric motor is 9.6 X 103 J. The motor accomplishes the task in 20 s
while drawing a current of 2.0 A. What is the potential difference across the motor.
12. A lightning discharge lasts for 2.0 X 10-2 s. The potential difference that causes the discharge
is 1 X 108 V. If 30 C of charge is moved, determine:
a) the electrical current present in the discharge.
b) the total energy released during the discharge.
13. The rating on a 12 V automobile battery is 60 A.h. This rating indicates that the battery will
operate continuously for 60 h when the current drawn is 1.0 A. It further means that the
battery will operate for 30 h when the current drawn is 2.0 A, or any combination that
multiplies to 60. Determine:
a) the operating length when the current is 180 A.
b) the total charge the battery can deliver.
c) the total electrical energy stored in the battery.
December 30,2013