JEE Mains · Physics · STD 12 - 3. current electricity
A uniform heating wire of resistance \(36\, \Omega\) is connected across a potential difference of \(240\, {V}\) The wire is then cut into half and potential difference of \(240\, {V}\) is applied across each half separately. The ratio of power dissipation in first case to the total power dissipation in the second case would be \(1: {x}\), where \({x}\) is........... .
- A \(4\)
- B \(40\)
- C \(0.4\)
- D \(400\)
Answer & Solution
Correct Answer
(A) \(4\)
Step-by-step Solution
Detailed explanation
First case \({P}_{1}=\frac{{V}^{2}}{{R}}=\frac{(240)^{2}}{36}\) Second case Resistance of each half \(=18 \,\Omega\) \({P}_{2}=\frac{(240)^{2}}{18}+\frac{(240)^{2}}{18}=\frac{(240)^{2}}{9}\) \(\frac{{P}_{1}}{{P}_{2}}=\frac{1}{4}\) \({x}=4.00\)
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