A filament bulb (500 W, 100 V) is to be used in a 230 V main supply. When a resistance R is connected in series, it works perfectly and the bulb consumes 500 W. The value of R Option 1) 230  Option 2) 46  Option 3) 26  Option 4) 13

P Prateek Shrivastava

As discussed in

if R=r -

$P_{max}=\frac{E^{2}}{4r}$

- wherein

Power delivered will be maximum

$\rho=VI$

$I=\frac{\rho }{V_{B}}=\frac{500}{100}=5A$

$V_{R}=IR\:\:\:\:\:\Rightarrow (230-100)=5R$

$R=26\: \Omega$

Option 1)

230

This option is incorrect.

Option 2)

46

This option is incorrect.

Option 3)

26

This option is correct.

Option 4)

13

This option is incorrect.

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