A coffee maker makes coffee by passing steam through a mixture of coffee powder, milk and water. If the steam is mixed at the rate of 50   g per minute in a mug containing 500   g of mixture, then it takes about t 0 seconds to make coffee at 70 ° C when the initial temperature of the mixture is 25 ° C . The value of t 0 is close to (ratio of latent heat of evaporation to specific heat of water is

Step-by-step solution

Let m gram of steam is condensed in the process of heating mixture from 25 ° C to 70 ° C Then, Heat lost by steam = Heat gained by mixture ⇒ Heat of condensation of steam + Heat given by water formed = Heat gained by mixture ⇒    m · L + m s w Δ T = M · s n Δ T = 500 × s w × ( 70 - 25 ) ⇒ m = 500 × s w × 45 L + 30 s w ⇒ m = 500 × 45 L s w + 30 ⇒ m = 500 × 45 ( 540 + 30 ) ≈ 40   g Now, in 1   min , 50