A wire of resistance 4Ω is stretched to twice its original length. The resistance of stretched wire would be

Home » A wire of resistance 4Ω is stretched to twice its original length. The resistance of stretched wire would be

Option A 16 Ω
Option B 2 Ω
Option C 4 Ω
Option D 8 Ω

Solution:

The correct option is option A.

According to the question, the volume of the wire remains the same. $A l = c o n s t a n t$ . So when the length is doubled, the area becomes half. This can be evaluated by making use of the formula:

$R = ρl/A$

A wire of resistance 4Ω is given. So, we get the new resistance as 4 times the initial value that is 16 ohms. Thus D is correct.

i

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