A 4-W night-light is plugged into a 120-V circuit and operates continuously for 1 year. Find the following: (a) the current it draws, (b) the resistance of its filament, (c) the energy consumed in a year. Group of answer choices0.033 A; 3600 W; 35 kWh0.033 V; 3600 kW; 35 kWh0.033 A; 3600 J; 35 Wh30 A; 3600 W; 35 kJ
Question
A 4-W night-light is plugged into a 120-V circuit and operates continuously for 1 year. Find the following: (a) the current it draws, (b) the resistance of its filament, (c) the energy consumed in a year. Group of answer choices0.033 A; 3600 W; 35 kWh0.033 V; 3600 kW; 35 kWh0.033 A; 3600 J; 35 Wh30 A; 3600 W; 35 kJ
Solution
(a) The current it draws can be calculated using Ohm's law, which states that the current (I) is equal to the power (P) divided by the voltage (V). So, I = P/V = 4W/120V = 0.033 A.
(b) The resistance of its filament can be calculated using Ohm's law in a different form, which states that the resistance (R) is equal to the voltage (V) divided by the current (I). So, R = V/I = 120V/0.033A = 3600 Ω.
(c) The energy consumed in a year can be calculated by multiplying the power by the time. The power is 4W, and the time is 1 year. However, we need to convert the time to hours because the power is in watts, which is joules per second, and there are 3600 seconds in an hour. So, the time in hours is 1 year * 365 days/year * 24 hours/day = 8760 hours. Therefore, the energy consumed is 4W * 8760 hours = 35,040 Wh, or 35 kWh.
So, the correct answer is 0.033 A; 3600 Ω; 35 kWh.
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