Question

In a certain solar house, energy from the Sun is stored in barrels filled with water. In a particular winter stretch of five cloudy days, 0.90 ? 10⁶ kcal per day is needed to maintain the inside of the house at 25.0

Answer 1

Since we know

Heat Lost by water = Heat gained by Room

Thus q_in = m * C * T

Where m is mass of water needed,

C is the specific heat of water, ( 1 kcal/g )

T is the change in temperature of water; Final - inital => 50 - 25

and thus q_in = 90 * 10^6 kcal/day * 5 days = 4.5  * 10^6 kcal

and q_in = m * 1kcal/kg * (50-25)

=> m = 180000 kg => v = m/density = 180000/1000 = 180 m³ or 180000 Litres (Answer)