Which of the following circular rods (given radius `r` and length `l`) each made of the same material and whose ends are maintained at the same temperature will conduct most heat?

Options

A. `r = 2r_(0), l = 2 l_(0)`
B. `r = 2r_(0), l = l_(0)`
C. `r = r_(0), l = l_(0)`
D. `r = r_(0), l = 2 l_(0)`

Answer

B

Explanation

(2) `i prop (1)/(R ) implies i prop (1)/(l//KA)`
`i prop (A)/(l) implies i (pi r^(2))/(l)`