Question 1: Explain how the motor effect is utilised in a loudspeaker to produce sound.

Answer: In a loudspeaker, an electric current flows through a coil of wire placed in a magnetic field. The motor effect causes a force on the coil, making it move back and forth. This movement vibrates the loudspeaker cone, producing sound waves.

Question 2: What are the main components of a typical loudspeaker that enable it to convert electrical signals into sound?

Answer: A coil of wire (voice coil), a permanent magnet, and a cone (diaphragm).

Question 1: Define the motor effect in physics.

Answer: The force experienced by a current-carrying conductor placed in a magnetic field, which causes movement.

Question 2: Describe how reversing the direction of current in the loudspeaker coil affects the movement of the cone.

Answer: Reversing the current reverses the direction of the force on the coil, causing the cone to move in the opposite direction.

Question 1: Calculate the force exerted on a coil of 200 turns, with a length of 0.05 m, carrying a current of 2 A in a magnetic field of 0.1 T. Use the formula F = BIL sin θ, assuming θ = 90°.

Answer: F = B × I × L × N = 0.1 T × 2 A × 0.05 m × 200 = 2 N

Question 2: If the force calculated above causes the cone to move back and forth with an acceleration of 50 m/s², what is the mass of the cone? (Use F = ma).

Answer: m = F / a = 2 N / 50 m/s² = 0.04 kg

Question 1: Identify three variables that could affect the efficiency of a loudspeaker's motor effect during an experiment.

Answer: Magnetic field strength, current in the coil, and the number of turns in the coil.

Question 2: Suggest two safety precautions that should be taken when working with loudspeaker components in a laboratory setting.

Answer: Ensure wires are insulated to prevent shocks and avoid short circuits by checking connections before powering on.

Question 1: A loudspeaker produces sound by moving its cone back and forth with a maximum velocity of 0.2 m/s. Explain how the velocity of the cone relates to the sound produced.

Answer: The velocity of the cone's movement causes pressure variations in the air, generating sound waves. Greater velocity results in louder sound.

Question 1: A loudspeaker coil has 500 turns and is placed in a magnetic field of 0.2 T. If the current in the coil is 3 A, calculate the magnetic force acting on the coil. Explain how this force contributes to sound production.

Answer: Using F = B I L N, where L is the length of the wire in the magnetic field. Assuming L = 0.1 m, F = 0.2 T × 3 A × 0.1 m × 500 = 30 N. This force causes the coil and attached cone to vibrate, producing sound waves.

Question 1: Explain how understanding the motor effect has contributed to the development of high-fidelity loudspeakers used in home entertainment systems.

Answer: The motor effect allows precise control of cone vibrations by adjusting current and magnetic fields, leading to clearer, more accurate sound reproduction in high-fidelity loudspeakers.