Task Sets: Electromagnetic Induction - OpenStax Physics (High School)

1.

Faraday's Law states that the magnitude of the induced EMF equals the rate of change of magnetic flux. Which expression is correct?

A.

$\varepsilon = \Phi_B \cdot \Delta t$

B.

$\varepsilon = \frac{\Delta\Phi_B}{\Delta t}$

C.

$\varepsilon = B \cdot A$

D.

$\varepsilon = \frac{\Delta B}{\Delta t}$

Three diagrams showing a magnetic field vector B at different angles to a loop: perpendicular to the loop (theta = 0), at 45 degrees, and parallel to the loop (theta = 90)

2.

A square loop has sides of length $0.10\ \text{m}$ (area $A = 0.01\ \text{m}^2$ ). A uniform magnetic field of $B = 0.50\ \text{T}$ is directed perpendicular to the loop ( $\theta = 0\degree$ ). Calculate the magnetic flux through the loop in webers.

3.

A circular loop of radius $r = 0.05\ \text{m}$ is in a magnetic field $B = 0.40\ \text{T}$ . The field makes an angle of $\theta = 60\degree$ with the normal to the loop. Calculate the magnetic flux through the loop in webers. Use $\pi \approx 3.14$ .

4.

A rectangular loop (area $A = 0.02\ \text{m}^2$ ) is perpendicular to a magnetic field ( $\theta = 0\degree$ ). The field changes from $B_1 = 0.30\ \text{T}$ to $B_2 = 0.80\ \text{T}$ in $\Delta t = 0.25\ \text{s}$ . Calculate the magnitude of the average induced EMF in volts.

5.

A strong permanent magnet is held stationary inside a conducting loop. The flux through the loop is large but constant. What is the induced EMF?

A.

A large EMF proportional to $B$ , since the field is strong.

B.

A moderate EMF proportional to $\Delta B / \Delta t$ .

C.

Zero — the flux is not changing, so no EMF is induced.

D.

An EMF that oscillates because the electrons in the loop respond to the field.

Exercises: Electromagnetic Induction

Recall / Warm-Up

Fluency Practice