Mirror: Reflects off of
Glass of water: Goes through
Dark Fabric: Absorbs into
Answer:
The correct answer would be 200m
Explanation:
20x10=200
the previous answer is incorect from the other user.
Answer:
The temperature of cold reservoir should be 246.818 K for efficiency of 35%
Explanation:
In first case we have given efficiency of Carnot engine = 26 % = 0.26
Temperature of cold reservoir 
We know that efficiency of Carnot engine is given by



For second Carnot engine efficiency is given as 35% = 0.35
And temperature of hot reservoir is same so 
So 

So the temperature of cold reservoir should be 246.818 K for efficiency of 35%