Two rods R and Q of same metal and same cross-section have length in the ratio `1:2` One end of each rod is at `0^(@)C` and temperatures of other are `30^(@)C` and `40^(@)C` respectively. Which of the rod will have higher flow of heat ?

Options

A. Rod P
B. Rod Q
C. Depends upon the shape
D. Both will have same.

Answer

A

Explanation

Here `Q=(DeltaT)/(l)`
`rArrQ_(1)prop(30)/(l)` and `Q_(2)prop(40)/(2l)`
`:.(Q_(1))/(Q_(2))=(30)/(40)xx(2l)/(l)=(3)/(2)`
`rArrQ_(1)gtQ_(2)`.
Hence correct choice is (a).