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If the length of the filament of a heater is reduced by `10%`, the power of the heater willA. increase by about `9%`B. increase by about `11%`C. increase by about `19%`D. decrease by about `10%` |
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Answer» Correct Answer - B `P=V^2/R` or `P prop 1/R` `P_2/P_1=R_1/R_1=l_1/l_2` (as R `prop` 1) `:. P_(2) = ((l_(1))/(l_(2))) P_(1) = ((l)/(0.9 l)) P_(1) = 1.11 P_(1)` so, power will increase by `11%` |
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