Tutorial 10 — Electromagnetism
Course: FAD1022 Basic Physics 2
Semester: 2 2025/2026
Centre: Centre for Foundation Studies in Science, Universiti Malaya (PASUM)
Question 1
An elastic metal loop of radius 12.0 cm is placed in a uniform magnetic field with magnetic flux density 0.8 T (Figure 1). The loop suddenly shrinks to a radius of 8.0 cm in 0.2 s.
Calculate:
a) The change in magnetic flux b) Determine the magnitude of induced emf in the loop c) State the direction of the induced current d. Find the magnitude of the induced current if the resistance of the loop is $1.0 \Omega$
Question 2
Calculate the peak emf generated by:
- A 0.250 m radius coil
- 500 turns
- Rotated one-fourth of a revolution in 4.17 ms
- Originally having its plane perpendicular to a uniform magnetic field, 0.425 T
Question 3
A 50-loop circular coil has a radius of 3.0 cm. It is oriented so that the field lines of a magnetic field are normal to the area of the coil. Suppose that the magnetic field is varied so that B increases from 0.10 T to 0.35 T in a time of 2.0 milliseconds.
Calculate the average induced emf in the coil.
Question 4
As shown in Figure 4, a metal rod contacts a partial circuit and completes the circuit. The circuit is perpendicular to a magnetic field with $B = 0.15 \text{ T}$.
Given:
- Resistance: $3.0 \Omega$
- Rod moving with constant speed: $2.0 \text{ m/s}$
Calculate:
a) How large a force is needed to move the rod as indicated with a constant speed of $2.0 \text{ m/s}$? b) Calculate the rate of dissipated energy in the resistor? c) Determine the direction of induced current.
Guide: Power, $P = I^2R$ or $P = Fv$
Question 5
A conducting rod of 50 cm moves to the right along a parallel metal rail with a velocity of $10 \text{ m/s}$. A uniform magnetic field of 2.0 mT acts at right angle into the plane of the railings.
Given:
- Resistance in the conducting rod: $10.5 \Omega$
Calculate:
a) The magnitude of the induced current in the rod if the two ends of the rod are connected by a wire of negligible resistance b) The direction of the induced current
Question 6
A sliding bar in Figure 6 has a length of 1.00 m and moves at a constant speed, $v$ in a magnetic field of magnitude 3.0 T. If the induced current in the resistor is 0.50 A, calculate $v$.
Related Concepts
- Magnetism
- Electromagnetic Induction
- Faraday's Law of Induction ($\varepsilon = -N\frac{d\Phi_B}{dt}$)
- Magnetic Flux ($\Phi_B = BA\cos\theta$)
- Motional EMF ($\varepsilon = Blv$)
- Lenz's Law
- Induced Current
- Eddy Currents