There are two wires of same material but length and diameter of first wire are double of the second wire. Then the resistance of first wire will be :-

double of the resistance of the second wire.

No worries! We‘ve got your back. Try BYJU‘S free classes today!

half of the resistance of te second wire.

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

equal to the resistance of the second wire.

No worries! We‘ve got your back. Try BYJU‘S free classes today!

fourth times the resistance of the second wire.

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is B half of the resistance of te second wire.
Resstance of first wire is $R_{1} = \frac{ρ l_{1}}{π (d_{1} / 2)^{2}}$ and resistance of 2nd wire is $R_{2} = \frac{ρ l_{2}}{π (d_{2} / 2)^{2}}$
Here, $l_{1} = 2 l_{2}, d_{1} = 2 d_{2}$
Thus, $R_{1} = \frac{ρ (2 l_{2})}{π (2 d_{2} / 2)^{2}} = R_{2} / 2$

Suggest Corrections

Similar questions

Q. A metallic wire has a resistance of

1 Ω

. A second wire of the same material of double the length and half of the radius of the first wire will have a resistance of _____.

Two wires made of copper wire are taken such that the length and area of cross-section of the second wire are twice and thrice respectively those of the first wire. If the resistance of the second wire is $12 Ω$ . Find the resistance of the first wire.

Q. There are two wires of same material and same length while the diameter of second wire is two times the diameter of first wire, then the ratio of extension produced in the wires by applying same load will be

Q. Resistance of a wire of uniform diameter and length

l

R .

The resistance of another wire of the same material but diameter

2 d

and length

4 l

will be

Q. If a wire of resistance R is stretched to double of its length keeping the diameter same, then new resistance will be:

Join BYJU'S Learning Program

There are two wires of same material but length and diameter of first wire are double of the second wire. Then the resistance of first wire will be :-

The correct option is B half of the resistance of te second wire.Resstance of first wire is R1=ρl1π(d1/2)2 and resistance of 2nd wire is R2=ρl2π(d2/2)2Here, l1=2l2,d1=2d2Thus,R1=ρ(2l2)π(2d2/2)2=R2/2