I'm sorry but I don't see anything that says part B
.
Answer:

Explanation:
Given that,
Efficiency of heat engine, 
Temperature of hot source, 
We need to find the temperature of cold sink i.e.
. The efficiency of heat engine is given by :




So, the temperature of the cold sink is 256.2°C. Hence, this is the required solution.
ok
1. blue red pink black
2. you can say bored look
3. why do you want to talk in brainly?
Answer:
Soru okunmuyor keşke fotoğrafını çekip atsaydın öyle atarsan sorunu çözerim
İYİ DERSLER
Let's start with the concept of momentum. What is it? Linear momentum in physics is mathematically written as a product of mass and velocity of an object. Now let us suppose a body of mass m is moving in an inertial frame of reference with velocity v. Consider the fact that no external force is acting on the system. The momentum of this body is given by mv, where m is the mass and v is its velocity. In case of simple real world problems not delving into the realms of relativity, mass is a conserved quantity and it cannot be zero. Hence the velocity of the body must be zero and hence the momentum.
However, photons are considered to have a rest mass zero.
However note the point carefully "rest mass". A body in motion cannot have mass to be zero.
<em>-</em><em> </em><em>BRAINLIEST</em><em> answerer</em><em> ❤️</em>