2. How much energy is dissipated as heat during a two-minute time interval by a 1.5-k2 resistor which has a constant 20-V potential difference across its leads? 3. A light bulb is rated at 30 W when operated at 120 V. How much charge enters (and leaves) the light bulb in 1.0 min? 4. If a mile of 24-gauge copper wire has a resistance of 0.14 k2 and the resistivity of copper is 1.7 x 108 Q2 m, what is the diameter of the wire? (1 mile = 1.6 km) 5. A nichrome wire and an aluminum wire, each with the same initial resistance, have the same change in resistance when heated separately. (PAI 2.82 × 10-8 m; αAI 3.9 x 10-³/°C; Phichrome 1.50 x 10-6 m; nichrome = 0.40 x 103°C.) The ratio of the temperature change of the nichrome wire to the temperature change of the aluminum wire is