1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

# A uniform wire of resistance 100 Ω is melted and recasted into a wire of length twice that of the original. The resistance of the new wire is _____.

A
100 Ω
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
200 Ω
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
300 Ω
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
400 Ω
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

## The correct option is D 400 ΩWe know that resistance, R=ρlA, where ρ is the specific resistance or resistivity of the material, l is the length of the material and A is the area of cross-section. In both the cases, the material remains the same, ρ will be constant. Also, volume of the wire, V=Al is also constant. ⟹A=Vl and resistance, R can be re-written as R=ρl2V So, R1R2=(l1)2(l2)2=l2(2l)2=14 Given, resistance R1=100 Ω ⟹R2=4R1=4×100=400 Ω Hence, the new wire will have a resistance of 400 Ω.

Suggest Corrections
12
Join BYJU'S Learning Program
Related Videos
PHYSICS
Watch in App
Explore more
Join BYJU'S Learning Program