Loudspeakers (physics Only) (ht Only) (GCSE Physics)

A voice-coil driven by an AC current has an instantaneous current of 0.21 A when the AC voltage across it is 3.0 V. What is the DC resistance (approximate) of the coil at that operating point (use V = IR)?

In a loudspeaker, if you increase the number of turns of the voice coil (keeping current the same), what is the effect on force for a coil occupying the same magnetic gap?

Which of the following explanations correctly states Lenz’s law in the context of a coil moving near a magnet?

In a two-way loudspeaker system the tweeter reproduces high frequencies while the woofer reproduces low frequencies. Why is the tweeter typically much smaller and lighter than the woofer?

A speaker designer wants to reduce mechanical resonance peaks in a loudspeaker’s response. Which practical measure will help to dampen the resonance?

A small section of voice-coil wire of length 0.65 m carries current 0.020 A in a field of 0.125 T. Use F = BIL to calculate the force and identify which option lists the correct calculation (showing the correct numeric result).

Why is a low-mass voice coil and diaphragm assembly preferred for reproducing transient sounds (quick attacks such as drum hits)?

The SI unit of magnetic flux density (B) is the tesla. Which combination of SI units is equivalent to 1 tesla?

Which phenomenon causes some energy to be lost as heat when the voice-coil and magnet assembly moves rapidly inside a metallic structure?

Why does the impedance (effective opposition to AC current) of a typical loudspeaker voice coil tend to increase at higher audio frequencies?

A loudspeaker cone attached to a coil is driven with a stronger alternating current amplitude. Which immediate change increases the sound pressure level (SPL) produced?