What are the operating resistance and current draw of a 250 W, 120 V infrared heat lamps?
The Correct Answer and Explanation is:
To determine the operating resistance and current draw of a 250 W, 120 V infrared heat lamp, we can use the power formula and Ohm’s law.
1. Current Draw (I):
We know that the power (P), voltage (V), and current (I) are related by the formula:P=VIP = VIP=VI
Rearranging this to solve for current (I):I=PVI = \frac{P}{V}I=VP
Substituting the given values for power (P = 250 W) and voltage (V = 120 V):I=250120=2.08 AI = \frac{250}{120} = 2.08 \, \text{A}I=120250=2.08A
So, the current draw of the heat lamp is 2.08 A.
2. Operating Resistance (R):
Next, we can use Ohm’s law to calculate the resistance (R). Ohm’s law states that:V=IRV = IRV=IR
Rearranging this to solve for resistance (R):R=VIR = \frac{V}{I}R=IV
Substituting the values for voltage (V = 120 V) and current (I = 2.08 A):R=1202.08=57.69 ΩR = \frac{120}{2.08} = 57.69 \, \OmegaR=2.08120=57.69Ω
So, the operating resistance of the heat lamp is 57.69 Ω.
Explanation:
- Power (P) is the amount of energy used per unit time. It’s given as 250 W, which means the lamp consumes 250 watts of power when in operation.
- Voltage (V) is the potential difference across the lamp’s terminals. In this case, it’s 120 V, which is the standard household voltage in many regions.
- Current (I) is the flow of electrical charge. The formula I=P/VI = P/VI=P/V helps us calculate how much current is drawn by the lamp based on its power rating and the supply voltage.
- Resistance (R) describes how much the lamp resists the flow of current. The formula R=V/IR = V/IR=V/I is derived from Ohm’s law and helps us understand the internal resistance of the lamp filament or heating element.
This analysis tells us how much current the lamp draws and the internal resistance it presents when powered on.
