Q. The area of the glass of a window of a room is $10\ m^{2}$ and thickness $2mm$. The outer and inner temperature are $40℃$ and $20℃$ respectively. Thermal conductivity of glass in MKS system is 0.2. The heat flowing in the room per second will be
A) $3 \times 10^{4}\ joules$
B) $2 \times 10^{4}\ joules$
C) $30\ joules$
D) $45\ joules$
Explanation
(b) $\frac{Q}{t} = \frac{KA(\theta_{1} - \theta_{2})}{l} = \frac{0.2 \times 10 \times 20}{2 \times 10^{- 3}} = 2 \times 10^{4}J/s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.