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Help me understand! Two electric bulbs marked 25 W-220 V and 100 W - 220 V are connected in series to a 440 V supply .Which of the bulbs will fuse?

Two electric bulbs marked  25 W-220 V and 100 W - 220 V are connected in series to a 440 V supply .Which of the bulbs will fuse?

  • Option 1)

    both

  • Option 2)

    100W

  • Option 3)

    25 W

  • Option 4)

    neither

Answers (2)
32 Views
N neha

 

As discussed in:

Series Grouping -

Potential - Different

Current - Same

- wherein

 

I_{1}=\frac{P_{1}}{V_{1}}

I_{1}=\frac{25}{220}Amp

Similarly,

I_{2}=\frac{P_{2}}{V_{2}}=\frac{100}{220}Amp

The current flowing through the circuit I=\frac{440}{Reff}

Reff= R_{1}+R_{2}

R_{1}= \frac{V^{2}_{1}}{P_{1}}=\frac{(220)^{2}}{25}

R_{2}= \frac{V^{2}_{2}}{P_{1}}=\frac{(220)^{2}}{100}

\therefore I=\frac{440}{\frac{(220)^{2}}{25}+\frac{(220)^{2}}{100}}

After solving this, we get I=\frac{40}{220}Amp

\because I_{1}(=\frac{25}{220}A)< I(=\frac{40}{220}A)<I_{2}(=\frac{100}{200}A)

Thus the bulb rated 25W-220V will fuse. 

 


Option 1)

both

Option 2)

100W

Option 3)

25 W

Option 4)

neither

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