- E The capacitance of a parallel-plate capacitor is C = Kε 0 A/d, where K is the
dielectric constant, A is the area of each plate, and d is their separation
distance. Decreasing d will cause C to increase.
- B The resistance of a wire made of a material with resistivity ρ and with
length L and cross-sectional area A is given by the equation R = ρL/A. Since
Wire B has the greatest length and smallest cross-sectional area, it has the
greatest resistance.
- A The amplitude of a wave is the maximum displacement from equilibrium
(the position of zero displacement). Since the distance between the maximum
positive displacement and the maximum negative displacement is 0.16 m, the
amplitude is half this: 0.08 m.
- D The graph shows two crests and one trough. So each has a length of 0.2 m,
which is a third of the total distance provided, 0.6 m. A full wavelength
consists of one crest and one trough, which in this case is 0.2 m + 0.2 m =
0.4 m.
