1. A 1.5 volt source is used to power a bulb. The filament wire of the bulb has a resistance of 20 ohms. Solve for the current flowing through the bulb. If the resistance of the bulb is increasing at 0.1 ohm/minute and at the same time, the voltage is being depleted at 0.2 volts/min, what is the rate of change on the current? (10 marks) 2. From P = W/t, I = Q/t, W = QV, express P as a function of I and V. (5 marks) 3. Three electrical devices, with ratings of 30 ohms, 50 ohms, and 60 ohms are connected in series to a 12 volt source. Draw the schematic diagram and the table and show all computations to fill up the table. (15 marks) 4. In problem 3, suppose you connect the three electrical devices are connected in parallel. Draw the schematic diagram and the table and show all computations to fill up the table. If the resistances of the electrical devices are increasing at 0.3 ohms/minute, 0.5 ohms/min, and 0.6 ohms/minute, respectively, what is the change in the total resistance?