Practice Electric Current in Physics

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Worksheet PDF Free Answer-key PDF Family

Quick Recap

Electric current is the rate at which electric charge flows past a point in a circuit or conductor.

Current is like the flow rate of water in a pipe — how much charge passes a point each second.

Showing a random 20 of 50 problems.

Example 1

challenge
A circuit has three parallel branches sharing 12 A12\ \text{A}. Branch 1 carries twice the current of branch 2, and branch 3 carries the same as branch 2. Find each branch current.

Example 2

medium
A current of 1.51.5 A flows for 4040 s. How much charge passes?

Example 3

medium
A phone charger delivers a steady current of 2.0 A2.0 \text{ A} for 30 minutes30 \text{ minutes}. How much total electric charge flows through the cable?

Example 4

medium
A 5 A current flows through a wire. A student says the current is smaller after the bulb. Is this correct, and why?

Example 5

easy
Convert 750 mA750\ \text{mA} to amperes.

Example 6

easy
A current of 1 A1\ \text{A} equals how many coulombs per second?

Example 7

hard
A circuit branch carries current I(t)=2t AI(t) = 2t\ \text{A} (with tt in seconds) from t=0t=0 to t=5 st=5\ \text{s}. Find the total charge passing in that interval.

Example 8

hard
In a circuit, 4.0 A4.0\ \text{A} flows for 30 s30\ \text{s}, then 0 A0\ \text{A} for 30 s30\ \text{s}, then 2.0 A2.0\ \text{A} for 60 s60\ \text{s}. Find the average current over the full 22 minutes.

Example 9

medium
A USB-C laptop charger delivers a steady 3.0 A3.0\ \text{A} for 45 minutes45\ \text{minutes}. How much charge flows through the cable?

Example 10

medium
A car battery delivers 50 A50\ \text{A} to a starter motor for 3 s3\ \text{s}. How much charge passes?

Example 11

medium
A student measures 300 mA300\ \text{mA} entering a bulb and reports 250 mA250\ \text{mA} leaving it. Is this physically possible? Briefly explain.

Example 12

easy
Does the same current that enters a resistor leave it, or is current 'used up'?

Example 13

easy
Two points in a circuit pass 66 C and 66 C in the same second. Is the current the same at both?

Example 14

medium
At a junction, 77 A flows in and one branch carries 44 A out. What current leaves the other branch?

Example 15

easy
True or false: at a junction in a circuit, the sum of currents in equals the sum of currents out.

Example 16

challenge
A junction has three branches: 55 A enters, 22 A leaves one branch, and the third branch's direction is unknown. If the second branch is measured at 66 A leaving, what is the third branch current and direction?

Example 17

hard
A single AA cell delivers 40 mA40\ \text{mA} for 25 hours25\ \text{hours} before dying. How much total charge did it provide?

Example 18

medium
A wire carries 4 A4\ \text{A} for 5 minutes5\ \text{minutes}. How many electrons pass through?

Example 19

easy
Convert 500500 mA to amperes.

Example 20

medium
A current of 250 mA250\ \text{mA} flows for 4 minutes4\ \text{minutes}. How much charge passes?
← Back to Electric Current Worked Examples Formula Explained