A lightbulb’s output is 60 W when it operates at 120 V. If the voltage is cut in half and the power dropped to 20 W during a brownout, what is the ratio of the bulb’s resistance at full power to its resistance during the brownout?
Answer to relevant QuestionsTo empty a flooded basement, a water pump must do work (lift the water) at a rate of 2.00 kW. If the pump is wired to a 240-V source and is 84% efficient, (a) How much current does it draw and (b) What is its resistance? A battery delivers 2.54 A to a resistor rated at 4.52Ω. When it is connected to a 2.21-Ω resistor, it delivers 4.98 A. Determine the battery’s (a) Internal resistance (assumed constant), (b) Emf, and (c) Terminal ...In a country setting it is common to see a hawk sitting on a single high-voltage electric power line searching for a roadkill meal (Fig. 17.19). To understand why this bird isn’t electrocuted, let’s do a ballpark ...Use Kirchhoff’s loop theorem to explain why the current in an RC circuit that is discharging a capacitor decreases as time goes on. Use the loop theorem to explain why the current in a charging RC circuit also decreases ...Light bulbs are labeled with their power output. For example, when a lightbulb is labeled 60 W, it is assumed that the bulb is connected to a 120- V source. Suppose you have two bulbs. A60- W bulb is followed by a 40- W bulb ...
Post your question