Question

A. The resistance of a 1m long
nichrome wire is 6 oham. If we reduce
the length of the wire to 70 cm
what will its resistance be?​

Answer 1

Answer:

Length = 1 m.

Resistance = 6 Ω.

Area if cross section = a

Now, Resistivity = Ra/l

p=1  

6∗a

​p=6a

In second case :-

Length = 70 cm = 0.7 m

Resistance = R

Area of cross section = a

Now, Resistivity =Ra/l

p=Ra/0.7

Since for the same material the resitivity will be same whether the area or the length either decrease or increase, therefore . from eq I and ii  

6a=Ra/0.7

R = 6 × 0.7  

R = 4.2 Ω.

pls mark me in brain list