Question 1: Define the generator effect in the context of microphones.

Answer: The generator effect is the process by which a changing magnetic field induces an electric current in a conductor.

Question 2: Explain how a microphone converts sound waves into electrical signals using the generator effect.

Answer: A microphone uses a diaphragm attached to a coil or magnetic components that move within a magnetic field when sound waves hit it. The movement causes a change in magnetic flux, inducing an electric current through electromagnetic induction, which represents the sound.

Question 1: What materials are commonly used for the coil and magnet inside a microphone? List at least two for each.

Answer: The coil is typically made of copper or aluminium wire, and the magnet is usually made of ferrite or neodymium.

Question 2: Describe the role of the diaphragm in the operation of a microphone.

Answer: The diaphragm vibrates in response to sound waves, causing movement of the coil or magnetic components that generate an electrical signal.

Question 1: A microphone coil has 200 turns and a length of 0.05 meters. If the coil moves within a magnetic field of flux density 0.1 Tesla at a velocity of 0.02 m/s, calculate the induced emf in the coil. Use the formula: emf = N × B × v × L, where N is the number of turns, B is magnetic flux density, v is velocity, and L is length.

Answer: emf = 200 × 0.1 × 0.02 × 0.05 = 0.0002 volts (or 200 μV)

Question 2: If the induced emf in a microphone coil is 5 millivolts when a sound causes a coil to move, and the coil has 150 turns, what is the change in magnetic flux (ΔΦ) through one turn? Use the relation emf = N × ΔΦ / Δt, assuming Δt = 1 second.

Answer: ΔΦ = emf / N = 0.005 V / 150 = 3.33 × 10⁻⁵ Weber (or Weber)

Question 1: Design a simple experiment to demonstrate how sound frequency affects the induced emf in a microphone coil. List the main variables involved and safety precautions.

Answer: An experiment can involve varying the sound frequency produced by a speaker and measuring the induced emf in a coil attached to a microphone. Main variables include sound frequency (independent), emf (dependent), coil number, and magnetic field strength. Safety precautions include avoiding exposure to loud sounds to prevent hearing damage, ensuring electrical connections are insulated, and handling magnets carefully to prevent pinching injuries.

Question 2: Identify two factors that could affect the accuracy of a microphone’s electrical signal in a recording studio.

Answer: Factors include electromagnetic interference from other electronic devices and mechanical vibrations or distortions of the diaphragm that can introduce noise.

Question 1: A professional recording microphone produces an electrical signal of 2 volts when a speaker emits a sound wave. If the coil has 250 turns, estimate the change in magnetic flux through the coil during this sound event, assuming Δt = 1 second.

Answer: ΔΦ = emf / N = 2 V / 250 = 0.008 Weber

Question 2: Explain how the principles of the generator effect are utilised in modern industry to improve audio recording and broadcasting technology.

Answer: The generator effect allows microphones to convert sound waves into electrical signals with high fidelity by electromagnetic induction. Advances such as dynamic and condenser microphones exploit these principles, enabling accurate sound capture. This technology is essential in professional recording studios, broadcasting, and live sound engineering, where clear and reliable audio signals are vital.