The first law of thermodynamics characterises the two types of energy transfer, as heat and as thermodynamic. The final internal (thermal) energy of the system is 1,500 J.
<h3>What is internal energy?</h3>
The energy present in a system itself for conducting reactions is called internal energy.
Given,
- Heat entering system (Q) = 700 J
- Work done by the piston (W) = 400
- Initial energy
= 1200 J
According to the <u>first law of thermodynamics</u>:

Substituting values in the above equation:

Therefore, option D. 1500 J is the final energy.
Learn more about internal energy here:
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The crest is cover distance. <span>The </span>speed<span> of a wave indicate how fast wave is moving. </span>T<span>he speed is the distance traveled by a crest in a given interval of time. Greater distance in same amount of time means wave travel faster.
speed of wave = distance/time.
speed of wave = 0,2 m </span>÷ 0,2 s = 1 m/s.
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Sorry I’m only answering so I could upload
francium , in the Periodic table the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. making helium is the smallest element, and francium the largest.