Question

If the length of the filament of a heater is reduced by `10%`, the power of the heater will
A. increaases by about `9%`
B. increases by about `11%`
C. increases by about `19%`
D. decreases by about `10%`

Answer 1

Correct Answer - B
`P=(V^(2))/Rimplies(P_(2))/(P_(1))=(R_(1))/(R_(2))=(l_(1))/(l_(2))=l/(0.9l)=10/9`
`P_(2)=1.11 P`
Increased about `11%`