- We can use Ohm's Law, which states that the voltage (V) across a resistor is directly proportional to the current (I) flowing through it, provided the temperature and other physical conditions remain unchanged (V = I R). - First, calculate the resistance (R) of the heater using the initial conditions: V1 = 220 V, I1 = 0.5 A. - R = V1 / I1 = 220 V / 0.5 A = 440 ohms. - Now, use this resistance to find the new current (I2) when the potential difference (V2) is 120 V. - V2 = I2 R - 120 V = I2 440 ohms - I2 = 120 V / 440 ohms = 12 / 44 A = 3 / 11 A. - Calculating the decimal value: 3 / 11 ≈ 0.2727 A.
The potential difference between the two end terminals of an electric heater is 220 V and the current through it is 0·5 A. What would be the current through the heater if the potential difference across the terminals of the heater is reduced to 120 V ?
Asked in UPSC NDA 2 2023 · Topic: Electric Current (Ohm's Law, resistance, resistivity, and conductivity)
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