Ohm's Law Practice Problems

Calculate current and convert to mA using Ohm’s Law:

Voltage (V) = 12

Resistance (R) = 6

Current (I) = ?

Current (I) = 2A or 2000 mA

Calculate resistance using Ohm’s Law:

Voltage (V) = 24

Current (I) = 6

Resistance (R) = ?

Resistance = 4

Calculate voltage using Ohm’s Law:

Voltage (V) = ?

Current (I) = 5

Resistance (R) = 8

Voltage = 40

Calculation current: If a light bulb has a resistance of 240 ohms and is connected to 120-volt power source, the current flowing through it can be calculated as:

Current = 0.5A or 500mA

Determining voltage: For a toaster that draws a current of 5 amperes and has resistance of 10 ohm’s, the voltage across it is:

Voltage = 50

Finding resistance: If a hairdryer operates at 220 volts and draws a current of 11 amperes, its resistance is:

Resistance = 20

Basic Current Calculation

A circuit with a 9 volt battery and a resistor of 3 ohms. What is the current flowing through the circuit?

Current = 3A or 3000mA

Resistance Determination

Find the resistance of a bulb that draws 0.5 amperes from 120 volt supply.

Resistance = 240

Voltage Calculation

What is the voltage across a resistor of 15 ohms through which a current of 2 amperes is flowing?

Voltage = 30

Multiple Resistors (Series)

In a series circuit with a 12 volt battery, if there are two resistors of 4 ohms and 6 ohms, what is the current flowing through the circuit?

Current = 1.2A or 1200mA

Multiple Resistors (Parallel)

Calculate the total resistance in a parallel circuit with two resistors of 5 ohms and 10 ohms. If the voltage of 12 volts is applied across the circuit, what is the total current flowing through the circuit?

Current = 3.6A or 3600mA

Combine Ohm’s Law and Power

A device using 18 watts of power is connect to a 9 volt battery. Calculate the current drawn by the device and determine the resistance of the device?

Current = 2A or 2000mA

Resistance = 4.5

Variable Resistance

If the current in a circuit is 0.25 amperes and the voltage is 10 volts, what must be the resistance?

Resistance = 40

Complex Circuit Analysis

In a circuit, a 6 ohm resistor and a 12 ohm resistor are connected in a series to a 9 volt battery. Calculate the current through each resistor.

Current = 0.5A or 500mA