Physicshard · Past Paper
A wire of resistance 4 Ohms is stretched to double its length. What is its new resistance?
A8 Ohms
B16 Ohms
C2 Ohms
D4 Ohms
✓ Correct Answer: B — 16 Ohms
When length doubles (L'=2L), the area halves (A'=A/2) because volume is constant. New R' = ρ(2L)/(A/2) = 4R = 4*4 = 16 Ohms.
Share this question
More from Physics
- Atmospheric pressure at sea level is approximately:
- The SI unit of pressure is:
- What happens to the kinetic energy of an object if its velocity is doubled?
- A particle moves along a circle of radius R. In half a revolution, what is the ratio of distance to displacement?
- Atmospheric pressure is 760 mm of Hg. What is this in Pascals? (Density of Hg = 13600 kg/m³, g = 9.8)