Four rods of length ℓ and radius r of the same material are kept at the same temperatures. Which of the rods conduct most heat?
Answer

ℓ =0.5 m r = 4 cm

ℓ =1 m r = 8 cm

ℓ =0.5 m r = 8 cm

ℓ =1 m r = 4 cm

Question

Four rods of length ℓ and radius r of the same material are kept at the same temperatures. Which of the rods conduct most heat?
Answer
		
ℓ =0.5 m r = 4 cm
		
ℓ =1 m r = 8 cm
		
ℓ =0.5 m r = 8 cm
		
ℓ =1 m r = 4 cm

anonymous · Answer

resistance of rod is proportional to l/A where l length A area of the rod
low resistance high conductance.

anonymous · Answer

so which one conducts the most heat? I got c

anonymous · Answer

you calculate l/A ok, in which case it's minimum?

anonymous · Answer

now I am confused

anonymous · Answer

you calculate l/A?

anonymous · Answer

what is A?

anonymous · Answer

For c it's minimum so its conductivity is high.

anonymous · Answer

and that means it the hottest na?

anonymous · Answer

yes

festinger · Answer

l/A =  ℓ/(pi r^2)