Electromagnetic Induction Practice
10 problems · instant feedback · full explanations
Changing magnetic flux induces EMF: ε = −NΔΦ/Δt. The minus sign is Lenz's law — induced effects oppose the change that caused them.
Q1.
What induces an EMF in a coil?
Multiple choice · Easy
Q2.
A 100-turn coil experiences flux change of 0.02 Wb in 0.5 s. What is the induced EMF magnitude? (V)
Numerical answer (V) · Medium
Q3.
What does Lenz's law say about the induced current's magnetic field?
Multiple choice · Easy
Q4.
A magnet sits motionless inside a coil. The induced EMF is:
Multiple choice · Medium
Q5.
A transformer has 100 primary turns, 20 secondary turns, and 240 V primary. What is the secondary voltage?
Numerical answer (V) · Hard
Q6.
An electric generator converts:
Multiple choice · Medium
Q7.
Lenz's law is essentially the principle of energy conservation applied to induction.
True / False · Easy
Q8.
A large steady magnetic flux through a coil induces a large EMF.
True / False · Medium
Q9.
Dropping a magnet through a copper tube falls slowly because of:
Multiple choice · Hard
Q10.
How fast must flux change in a 50-turn coil to induce 10 V? (Wb/s)
Numerical answer (Wb/s) · Hard