Question

An air-filled parallel-plate capacitor of capacitance 12 nF has a 9 V battery connected
across it.
a) If the battery is first disconnected and then a dielectric of K = 3 is inserted between
the plates, what is the new capacitance, new charge, and new potential difference on the
capacitor?

b) How much work is required to remove the dielectric in part a?

2) A nickel wire of length 10 m and radius 2 mm has a potential difference of 1.5 V placed
across it. What is the power dissipated in the wire if the temperature is 80°C? (For nickel,
the resistivity at 20°C is ρ = 6.85x10-8 Ω-m, and the thermal coefficient is alpha = 6.41x10-3
(°C)-1.)

Answer 1