Question
Physics Question on Thermodynamics
An ice cube of dimensions 60 cm × 50 cm × 20 cm is placed in an insulation box of wall thickness 1 cm. The box keeping the ice cube at 0°C of temperature is brought to a room of temperature 40°C. The rate of melting of ice is approximately. (Latent heat of fusion of ice is 3.4×105 Jkg–1and thermal conducting of insulation wall is 0.05 Wm–1°C–1)
A
61×10−3kgs−1
B
61×10−5kgs−1
C
208kgs−1
D
30×10−3kgs−1
Answer
61×10−5kgs−1
Explanation
Solution
**The rate of melting of ice is : **
ΔtΔQ=lkA(T1−T2)
⇒ΔtmL=lkA(T1−T2)
⇒Δtm=LlkA(T1−T2)
≈61.1×10−5kg/s
Hence, the correct option is (B): 61×10−5kgs−1