A glass window conducts out a certain quantity of heat per second when the inside temperature is -10°C and the outside temperature is 10°C. The same quantity of heat will be conducted in through the window per second when the inside temperature is -43°C and the outside temperature is

Q: A glass window conducts out a certain quantity of heat per second when the inside temperature is -10°C and the outside temperature is 10°C. The same quantity of heat will be conducted in through the window per second when the inside temperature is -43°C and the outside temperature is

(a) 43°C

(b) -23°C

(c) 23°C

(d) 0°C

Ans: (b)

Sol: As , $\large i = \frac{\Delta T}{R}$

Let outside temperature is T°C

Hence , $\large \frac{10 -(-10)}{R} = \frac{T-(-43)}{R} $

20 = T + 43

T = -23°C