## Question 1

**a)** Explain the origin of magnetic fields in terms of moving charges. [3]

**b) **A straight wire carries a current of 5 A. Calculate the magnetic field strength at a distance of 2 cm from the wire. [3]

## Question 2

**a)** Describe the representation of magnetic fields using field lines. [3]

**b)** A solenoid has 100 turns and carries a current of 0.5 A. If the length of the solenoid is 20 cm, calculate the magnetic field strength inside the solenoid. [3]

## Question 3

**a) **Define electromagnetic induction. [3]

**b)** A coil with 200 turns is placed in a magnetic field that changes at a rate of 0.02 T/s. Calculate the induced EMF in the coil. [3]

## Question 4

**a)** Describe how the magnetic field due to a current-carrying conductor varies with distance from the conductor. [3]

**b) **A coil with 150 turns has a radius of 10 cm. If a magnetic field of 0.05 T is applied perpendicular to the plane of the coil, calculate the magnetic flux through the coil. [3]

**c)** If the magnetic field in part b) decreases to zero in 2 seconds, determine the induced EMF in the coil. [4]

## Question 5

**a)** Explain the principle behind electromagnetic induction in terms of Faraday's and Lenz's laws. [3]

**b)** A straight wire 1 m long moves at a speed of 2 m/s perpendicular to a magnetic field of 0.1 T. Calculate the induced EMF in the wire. [3]

**c)** How would the induced EMF change if the wire moved parallel to the magnetic field? [2]

## Question 6

**a)** Differentiate between the magnetic field produced by a solenoid and a single loop of wire carrying the same current. [3]

**b)** A solenoid of length 30 cm has 300 turns and carries a current of 1 A. Calculate the magnetic field strength inside the solenoid. [3]

**c)** How would the magnetic field strength change if the number of turns was doubled, but the current was halved? [3]

## Question 7

**a)** Describe the factors that affect the resistivity of a material. [3]

**b)** A wire has a resistance of 5 ohms at 20°C. If its temperature coefficient of resistance is 0.004/°C, calculate its resistance at 50°C. [3]

**c)** How does the drift velocity of electrons in a conductor relate to the current flowing through it? [3]

## Question 8

**a)** Describe the origin of magnetic fields in terms of moving charges. [3]

**b)** A straight conductor of length 2 m carries a current of 3 A. If it is placed in a magnetic field of strength 0.5 T at an angle of 30° to the field, calculate the magnetic force acting on it. [3]

**c) **If the same conductor is shaped into a loop, how would the net magnetic force on it change when placed in the same magnetic field? [2]

**d)** Explain why transformers only work with alternating current (AC) and not direct current (DC). [3]

## Question 9

**a)** Explain the significance of the right-hand rule in determining the direction of the magnetic field due to a current-carrying conductor. [3]

**b)** A solenoid has a length of 40 cm and consists of 400 turns. If it carries a current of 2 A, calculate the magnetic field strength inside the solenoid. [4]

**c)** Describe the effect on the magnetic field strength if the solenoid is filled with a ferromagnetic material. [3]

**d)** How does the magnetic field due to a solenoid compare with that of a bar magnet? [3]

## Question 10

**a)** Define electromagnetic induction. [2]

**b)** A coil with 500 turns and a cross-sectional area of 0.02 m^2 is placed in a magnetic field that changes from 0.1 T to 0.5 T in 0.5 seconds. Calculate the induced EMF in the coil. [4]

**c)** State Lenz's law and explain its significance in the context of energy conservation. [3]

**d)** How does the principle of electromagnetic induction find application in electric generators? [3]