Question

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?

• A. r = 2r0 ; I=2l0
• B. r = 2r0 ; l=l0
• C. r = r0 ; l= l0
• D. r = r0 ; l=2l0

Answer 1

Answer: (B)

r = 2r0 ; l=l0

Answer 2

Heat=KA $\triangle \,\theta_x$

=K$\pi$r2$\frac{\triangle \,\theta}{1}$

For option B the value of H will be more.

Therefore, the correct option is (B): r = 2r0 ; l=l0