Conside the situation shown in figure. The frame is made of the same material and has a unifrom cross-section area everywhere. Calculate the amount of heat flowing per second through a cross section of the bent part if the total heat taken out per second from the end at `100^(@)C` is `130J` .

Explanation

(Q/t)_(AB)=(Q/t)_(Bent)+(Q/t)_(Straight)`
`(Q/t)_(Bent)=(KA(theta_1-theta_2))/(70)`
(Q/t)_(Straight)=(KA(theta_1-theta_2))/(60)`
`(Q/t)_(Bent)/(Q/t)_(straight)=60/70=6/7`
`implies(Q/t)_(Bent)+(Q/t)_(Straight)=130`
`(Q/t)_(Bent)+(Q/t)_(Bent)xx7/6=130`
`implies((7/6)+1)(Q/t)_(Bent)=130`
`implies13/6xx(Q/t)_(Bent)=130`
`(Q/t)_(Bent)=(130xx6)/13=60 J//s.`