Physicshard · Past Paper
A wire of resistivity 'rho' is stretched so that its length increases by 10%. What is the approximate percentage increase in its resistance?
A10%
B20%
C21%
D100%
✓ Correct Answer: C — 21%
If L becomes 1.1L, Area becomes A/1.1 (constant volume). R' = ρ(1.1L)/(A/1.1) = 1.21 * R. Increase is 21%.
Share this question
More from Physics
- A plane mirror forms what kind of image?
- What is the area under a velocity-time graph?
- A racing car has a uniform acceleration of 4 m/s^2. What distance will it cover in 10s after start?
- In a vacuum, if a feather and a coin are dropped from the same height:
- A body is thrown vertically upwards. At the highest point, it has: