Question

if the resistance of the wire is increased by twice its length, and its cross sectioned area decreased find the new resistance.

Answer 1

Heyy

It's sneha

Here is ur answer

⏩ As the resistance is directly proportional to length

➡ If we increase the length twice, the resistance of conductor also become twice of its original resistance

⏩ Area of Cross section is inversely proportional to the resistance

➡ If we decrease the area, the resistance increases

Hope it helps

#sneha

Answer 2

Let length of old wire be L1 and that of the new wire be L2.

According to the given condition,
L2 = 2× L1 ....(I)

Let the cross sectional area of old wire be A1 and that of new wire be A2

According to the given condition,
2×A2 = A1 ....(II)

We know that,
R = L/A

R2 = L2 /A2

i.e. R2 = 4L1 / A1 ...[From (I) and (II)]