Q108 / 180 · AIIMS 2008 · Physics

A bulb of \(25 \mathrm{~W}, 200 \mathrm{~V}\) and another bulb of \(100 \mathrm{~W}, 200 \mathrm{~V}\) are connected in series with a supply line of \(220 \mathrm{~V}\). Then

  • A
    both bulbs will glow with same brightness
  • B
    both bulbs will get fused
  • Correct answer
    C
    \(25 \mathrm{~W}\) bulb will glow more brightly
  • D
    \(100 \mathrm{~W}\) bulb will glow more brightly.

Solution

Resistance of $25 \mathrm{~W}, 200 \mathrm{~V}$ bulb $R_1=\frac{(200)^2}{25} \Omega$ Resistance of $100 \mathrm{~W}, 200 \mathrm{~V}$ bulb $R_2=\frac{(200)^2}{100} \Omega$. Clearly, $R_1>R_2 . \quad \therefore \quad H_1>H_2$. $\therefore 25 \mathrm{~W}$ bulb will glow more brightly.

Hence, the correct answer is option: 'C'.

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