Two identical rods of length `(L)`, area of cross-sectional `(A)` and thermal conductivity `k` are joined end to end. If temperature difference of free ends is `DeltaT`, the heat `Q_(0)` flows along rods per second. Find the total heat flowing per second along the rods if the two rods are placed parallel and temperature difference of free ends is `DeltaT`. There is no heat loss from curved surface.

Options

A. `Q=4Q_(0)`
B. `Q=2Q_(0)`
C. `Q=Q_(0)//4`
D. `Q=Q_(0)//2`

Explanation

For series connection
`R_(Q)Q_(0)=DeltaT`
`Q_(0)((L)/(AK)+(L)/(K_(2)A))=DeltaT`
`(2Q_(0)L)/(kA)=DeltaTrArr2RQ_(0)=DeltaT`
For parallel connection
`(AK)/(L)+(AK)/(L)=(1)/(R')rArrR'=R//2`
`DeltaT=Q((R )/(L))rArrQ=(2DeltaT)/(R )=4((DeltaT)/(2R))=4Q_(0)`