1.56× 105 J of heat is conducted through 2 m2 wall of 12 cm thick in 1 h . Temperature difference between the two sides of the wall is 20° C . The thermal conductivity of the material of the wall is (in W m- 1 K- 1 ) α . Write the value of 100α .

Question

1.56× 105 J of heat is conducted through 2 m2 wall of 12 cm thick in 1 h . Temperature difference between the two sides of the wall is 20° C . The thermal conductivity of the material of the wall is (in W m- 1 K- 1 ) α . Write the value of 100α . (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

Rate of heat flow, ( d Q/ d t)=(K A Δ T/x) ⇒ (1.56 × 105/3600)=(K × 2 × 20/12 × 10-2) ⇒ K=(1.56 × 105 × 12 × 10-2/3600 × 2 × 20) =(1.56/12)=0.13

Q. $1.56 \times 1 0^{5} J$ of heat is conducted through $2 m^{2}$ wall of $12 c m$ thick in $1 h$ . Temperature difference between the two sides of the wall is $2 0^{\circ} C$ . The thermal conductivity of the material of the wall is (in $W m^{- 1} K^{- 1}$ ) $α$ . Write the value of $100 α$ .

Rate of heat flow, $\frac{d Q}{d t} = \frac{K A Δ T}{x}$
$\Rightarrow \frac{1.56 \times 1 0 ^{5}}{3600} = \frac{K \times 2 \times 20}{12 \times 1 0 ^{- 2}}$
$\Rightarrow K = \frac{1.56 \times 1 0 ^{5} \times 12 \times 1 0 ^{- 2}}{3600 \times 2 \times 20}$
$= \frac{1.56}{12} = 0.13$

Q. 1.56×105J of heat is conducted through 2m2 wall of 12cm thick in 1h . Temperature difference between the two sides of the wall is 20∘C . The thermal conductivity of the material of the wall is (in Wm−1K−1 ) α . Write the value of 100α .

Rate of heat flow, dtdQ​=xKAΔT​ ⇒36001.56×105​=12×10−2K×2×20​ ⇒K=3600×2×201.56×105×12×10−2​ =121.56​=0.13

Q. $1.56 \times 1 0^{5} J$ of heat is conducted through $2 m^{2}$ wall of $12 c m$ thick in $1 h$ . Temperature difference between the two sides of the wall is $2 0^{\circ} C$ . The thermal conductivity of the material of the wall is (in $W m^{- 1} K^{- 1}$ ) $α$ . Write the value of $100 α$ .

Rate of heat flow, $\frac{d Q}{d t} = \frac{K A Δ T}{x}$
$\Rightarrow \frac{1.56 \times 1 0 ^{5}}{3600} = \frac{K \times 2 \times 20}{12 \times 1 0 ^{- 2}}$
$\Rightarrow K = \frac{1.56 \times 1 0 ^{5} \times 12 \times 1 0 ^{- 2}}{3600 \times 2 \times 20}$
$= \frac{1.56}{12} = 0.13$