Explanation:
Light is not invisible
sound cant travel in a vacuum
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<h3>Explanation</h3>
The Stefan-Boltzmann Law gives the energy radiation <em>per unit area</em> of a black body:
where,
the total power emitted, 
the surface area of the body, 
the Stefan-Boltzmann Constant, and
the temperature of the body in degrees Kelvins.
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.
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Keep as many significant figures in as possible. The error will be large when is raised to the power of four. Also, the real value will be much smaller than 
since the emittance of a human body is much smaller than assumed.
The vaccine ofcourse. They helped in making the vaccine.
Answer: The final temperature is 470K
Explanation: Using the relation;
Q= ΔU +W
Given, n = 2mol
Initial temperature T1= 345K
Heat =Q= 2250J
Workdone=W=-870J(work is done on gas)
T2 =Final temperature =?
ΔU =3/2nR(T2-T1)
ΔU=3/2 × 2 ×8.314 (T2 - 345)
ΔU=24.942(T2-345)
Therefore Q = 24.942(T2-345)+ (-870)
2250=24.942(T2-345)+ (-870)
125.09=(T2-345)
T2 =470K
Therfore the final temperature is 470K
