The only reasonable choice from this list is choice-A.
        
                    
             
        
        
        
Answer:
b) 20 kJ
Explanation:
Efficiency of carnot engine = (T₁ - T₂ ) / T₁  Where T₁ is temperature of hot source  and T₂ is temperature of sink .
T₁ = 270 + 273 = 543K
T₂ = 50 + 273 = 323 K 
Putting the given values of temperatures 
efficiency = (543 - 323) / 543 
= .405 
heat input = 50 KJ 
efficiency = output work / input heat energy 
.405 = output work / 50 
output work = 20.25 KJ. 
= 20 KJ . 
 
        
             
        
        
        
Answer:

Explanation:
Given:
mass of ice melted, 
time taken by the ice to melt, 
latent heat of the ice, 
Now the heat rejected by the Carnot engine:



Since we have boiling water as hot reservoir so:

The cold reservoir is ice, so:

Now the efficiency:



Now form the law of energy conservation:
Heat supplied:

where:
 heat supplied to the engine
 heat supplied to the engine




Now the work done:



 
        
             
        
        
        
Space telescopes have the advantage of being above the blurring effects of the Earth's atmosphere. 
A surrounding is a layer of fuel or layers of gases that envelop a planet and is held in a region through the gravity of the planetary frame. A planet retains its surroundings whilst the gravity is exceptional and the temperature of the surroundings is low. A stellar ecosystem is the outer area of a celeb, which includes the layers above the opaque photosphere; stars of low temperature may have outer atmospheres containing compound molecules.
The atmosphere of Earth consists of nitrogen (78%), oxygen (21%), argon (0.9%), carbon dioxide (0.04%), and trace gases. most organisms use oxygen for breathing; lightning and bacteria perform nitrogen fixation to provide ammonia that is used to make nucleotides and amino acids; flora, algae, and cyanobacteria use carbon dioxide for photosynthesis. 
The layered composition of the ecosystem minimizes the damaging results of daylight, ultraviolet radiation, solar wind, and cosmic rays to defend organisms from genetic harm. The modern composition of the atmosphere of the Earth is made from billions of years of biochemical modification of the paleo atmosphere by residing organisms.
To learn more about the atmosphere visit here:
brainly.com/question/26767532
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