H2 Physics Flashcards

What is the meaning of 'capacitance'?

Answer: The charge stored per unit potential difference: C = Q/V

Capacitance C = Q/V, where Q is the charge stored and V is the potential difference across the capacitor. Measured in farads (F).

Two capacitors of 4μF and 6μF are connected in series. What is the combined capacitance?

Answer: 2.4μF

1/C = 1/4 + 1/6 = 3/12 + 2/12 = 5/12. C = 12/5 = 2.4μF.

What is the threshold frequency in the photoelectric effect?

Answer: The minimum frequency of light needed to emit electrons from a metal surface

The threshold frequency (f₀) is the minimum frequency of incident light below which no photoelectric emission occurs, regardless of intensity. E_photon = hf₀ = work function (φ).

What is the Doppler effect?

Answer: The apparent change in frequency of a wave due to relative motion between source and observer

The Doppler effect is the apparent change in frequency (or wavelength) of a wave when the source and observer are moving relative to each other — frequency increases when approaching, decreases when receding.

What is the formula for the period of a mass-spring system in SHM?

Answer: T = 2π√(m/k)

The period of a mass-spring system: T = 2π√(m/k), where m is the mass and k is the spring constant. More mass = longer period; stiffer spring = shorter period.

Define electric potential at a point.

Answer: The work done per unit positive charge in moving a small positive test charge from infinity to that point

Electric potential at a point is the work done per unit positive charge in bringing a small positive test charge from infinity (reference point, V=0) to that point.