A `1^(@) C` rise in temperature is observed in a conductor by passing a certain current . If the current is doubled , then the rise in temperature is approximately

Options

A. `8^(@)C`
B. `12^(@)C`
C. `10^(@)C`
D. `36^(@)C`

Answer

d

Explanation

Heat produced in a wire of resistance `R` in passing the current `I` for time `t` is `H = I^(2) R t`
Heat required to raise the temperature of a wire of mass `m` sp heat `x` by `DeltaT` is `H' = mx = ms DeltaT`
`:. ms Delta T = I^(2) R t`
or `Delta T` (`m, s,R ant t `are fixed quentities
`:. (Delta T_(2))/(Delta T_(1)) = ((I_(2))/(I_(1)))^(2) = ((3I_(1))/(I_(1))) = 9`
`Delta T_(2) = 9Delta T_(1)= 9 xx 4 = 36^(@)C`