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27/07/2021 12:41 pm
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An electric iron is connected to the mains power supply of 220 V. When the electric iron is adjusted at ‘minimum heating’ it consumes a power of 360 W but at ‘maximum heating’ it takes a power of 840 W. Calculate the current and resistance in each case.
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27/07/2021 12:46 pm
Given: V = 220V, Pmin = 360W, Pmax = 840 W
For minimum heating case:
We know that
Pmin = VI
360 = 220 x I
I = 1.63 amp
R = \(\frac{V}{I}\)
R = \(\frac{220}{1.63}\)
R = 134.96 ohms
For maximum heating case:
We know that
Pmax = VI
840 = 220 x I
I = 3.81 amp
R = \(\frac{V}{I}\)
R = \(\frac{220}{3.81}\)
R = 57.74 ohms