Download Ohm`s Law Homework

Electric Circuit Problem Set
Ohm's Law Homework
1. Find the resistance of an electric light bulb if there is a current of 0.8 A and a potential
difference of 120 V.
2. What is the potential difference across a toaster of 13.7  resistance when the current
through it is 8.75 A?
3. What is the current through an electric heater with a resistance of 38  when the potential
difference is 240 V?
4. A light bulb uses 1.2 A when connected across a 120 V source. What power is dissipated by
the bulb?
5. What current flows through a 75 W bulb connected to a 120 V outlet? Ans: 0.625 A
6. A 6 V battery delivers 0.5 A of current to an electric motor. What power is dissipated by the
motor? How much electrical energy does it use in 5 min?
Series Circuits Homework
For each problem, draw the circuit diagram using appropriate symbols and meters.
7. A 10 , a 15 , and a 5  resistor are connected in series across a 90 V battery. Find the
total resistance of the circuit. What is the current through each resistor?
8. A 20  and a 30  resistor are connected in series across a 110 V potential difference. What
is the total resistance of the circuit? What is the current through each resistor? What is the
voltage drop across each resistor?
9. A 3 , a 5 , and a 4  resistor are connected in series across a 12 V battery. What is the
total resistance of the circuit? What is the current through each resistor? What is the voltage
drop across each resistor?
10. A 60 , a 90 , and an unknown resistor are connected in series across a 130 V battery. An
ammeter in the circuit reads 0.67 A. What is the total resistance of the circuit? What is the
size of the unknown resistor? What is the power dissipated in each resistor?
Parallel Circuits Homework
11. Three 15  resistors are connected in parallel across a 3 V battery. Find the total resistance
of the circuit. What is the total current? What is the current through each resistor?
12. A 120 . a 60 , and a 40  resistor are connected in parallel and placed across a 120 V
potential difference. What is the total resistance of the circuit? What is the total current?
What is the current through each resistor?
13. A 40 , a 8 , and a 10  resistor are connected in parallel across a 120 V battery. What is
the total resistance of the circuit? What is the circuit current? What is the current through
each resistor? What is the power dissipated?
14. A 12 , a 15 . and an unknown resistance are connected in parallel. The total current of
the combination is 12 A. The current across the 15  branch is 4 A. What is the total
voltage? What is the total resistance? What is the unknown resistance?
Complex Circuit Homework
15. A 12  resistor, a 10  resistor, and a 15  resistor are connected in parallel. This parallel
combination is in series with a 6  resistor and also in series with an 8  resistor. Calculate
the total resistance, the circuit current, the current through each resistor, and the voltage drop
across each resistor. A 36 V battery is used.
16. A 7  resistor is in parallel with a 3  resistor. This parallel combination is in series with a
5.4  resistor. A 30 V battery is used. What is the equivalent resistance of the entire circuit?
What is the total current?
17. A 7 , a 1 , and a 10  resistor are in series. This series combination is then in parallel
with a 6  resistor. The combination of the four resistors is then in series with a 10.3 
resistor. A 20 V battery is used. What is the equivalent resistance of the entire circuit? What
is the total current? What is the voltage drop across the 6  resistor? What is the current
through the 1  resistor?
18. Calculate the total current. Calculate the voltage drop across the 36  resistor. Calculate the
voltage drop across the 16  resistor. Calculate the current through the 48  resistor.
19. Calculate the total current. Calculate the voltage drop across the 8  resistor. Calculate the
voltage drop across the 12  resistor. Calculate the current passing through the 12 
resistor.