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1.56 × 10^5 J of heat is conducted throu...

`1.56 × 10^5 J` of heat is conducted through is `2 m^2` wall of 12 cm thick in one hour. Temperature difference between the two sides of the wall is `20 ^@C.` The thermal conductivity of the material of the wall is (in `Wm ^(-1) K^(-1)`)

A

`0.11`

B

`0.13`

C

`0.15`

D

`1.2`

Text Solution

Verified by Experts

The correct Answer is:
B
Rate of heat flow through the wall is
`(Delta Q)/(Delta t) =(KA Delta T)/( t)`
Subtitiing the given values we get
` (1.56 xx 10^5 J )/(3600 s ) = (K xx 2 m^2 xx 20 ^@ C )/( 12 xx 10^(-2) m)`
`k=( 1.56 xx 10^5 xx 12 xx 10^(-2))/( 3600 xx 2xx 20 ) W m^(-1) K^(-1)`
` = ( 1.56 )/(12) W m^(-1) K^(-1) = 0.13 W m^(-1) K^(-1)`
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