A constant voltage is applied between the two ends of a metallic wire. Some heat is developed in it. The heat developed is doubled if Options: A . &nbspboth the length and the radius of the wire are halved B . &nbspboth the length and the radius of the wire are doubled C . &nbspthe radius of the wire is halved D . &nbspthe length of the wire is doubled

Answer: Option B : B Q = V 2 R But R = p l π r 2 Therefore Q = ( π V 2 p ) r 2 1 Q is doubled if both l and r are doubled

A constant voltage is applied between the two ends of a metallic wire. Some heat

Question

A constant voltage is applied between the two ends of a metallic wire. Some heat is developed in it. The heat developed is doubled if

Options:

A . both the length and the radius of the wire are halved

B . both the length and the radius of the wire are doubled

C . the radius of the wire is halved

D . the length of the wire is doubled

Answer: Option B
:
B

Q = \frac{V^{2}}{R}

But

R = \frac{p l}{π r^{2}}

Therefore

Q = (\frac{π V^{2}}{p}) \frac{r^{2}}{1}

Q is doubled if both l and r are doubled

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