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What would be the resistance of and the current drawn by a 3kw 240 v immersion heater?
Wiki User
∙ 13y ago
Power = E2 / R
Resistance = E2 / power = (240)2 / 3,000 = 19.2 ohms
Current = E / R = 240 / 19.2 = 12.5 amperes
Wiki User
∙ 13y ago
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The Storage battery of a car has an emf of 12 volt if the internal resistance of the battery is 0.4 resistance what is the maximum current that can be drawn from the battery?
You have to imagine the internal resistance as being in parallel with any load you connect. You get the maximum possible current when the load is zero. In this case, just apply Ohm's Law. That is, divide the voltage by the internal resistance.
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If you doubled the load resistor in a wheatstone bridge. the load current would not be half as much Why not?
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Ohm's Law says Voltage = Current x Resistance With constant voltage, an increase in resistance decreases the current. Now the load can be added in two basic ways. If the load is added in series the resistance will increase. If you add load in parallel the resistance will decrease and the current will increase from the source.
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No, lower voltage equipment will not operate on a higher voltage because the wattage or current drawn by the equipment will be higher that the rating of the equipment at the lower voltage. For example if you take a heater rated at 5000 watts at 208 volts, the current is I = W/E 5000/208 = 24 amps. The resistance of this heater is R = W/I (squared) = 5000/24 x 24 (576) = 8.6 ohms. Applying 240 volts to this heater whose resistance is 8.6 ohms results in this new heater wattage rating. W = E (squared)/R = 240 x 240 (57600)/8.6 = 6697 watts. As you can see the original wattage of the heater is overloaded by about 25% of what the manufacturers specified the wattage to be. Ohms law states that the current is directly proportional to the applied voltage and inversely proportional to the resistance of the circuit. W = watts, I = amperage, R = resistance in ohms and E = voltage.
The Storage battery of a car has an emf of 12 volt if the internal resistance of the battery is 0.4 resistance what is the maximum current that can be drawn from the battery?
You have to imagine the internal resistance as being in parallel with any load you connect. You get the maximum possible current when the load is zero. In this case, just apply Ohm's Law. That is, divide the voltage by the internal resistance.
