A) \[\frac{1}{2}\]
B) \[2\]
C) \[\frac{1}{4}\]
D) \[4\]
Correct Answer: A
Solution :
Key Idea : Power is inversely proportional to resistance provided potential difference remains constant. The rate of dissipation of electric energy is called electric power. \[W=Vit\]. The electric power dissipated will be is given by \[P=\frac{W}{t}=\frac{Vit}{t}=Vi\] \[P=\frac{{{V}^{2}}}{R}\] ?. (i) When resistance is doubled, then let electric power is \[P\]. \[\therefore \] \[P=\frac{{{V}^{2}}}{2R}\] ... (ii) From Eqs. (i) and (ii), we get \[P=\frac{1}{2}P\] So, power becomes \[\frac{1}{2}\] of initial value.
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