Answer:
A=
Explanation:
We have given power =40 W but only 10% of this power is used so actual power 
We know that from Stefan's law
where
is Boltzmann constant which value is 
So
A=
That would be the atom I believe.
Answer:
This is because it has ns1 electron configuration like the alkali metals.
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From the calculations, the final momentum of B is 8.16 m/s
<h3>What is conservation of linear momentum?</h3>
According to the principle of the conservation of linear momentum, the momentum before collision is equal to the total momentum after collision.
This implies that;
MaUa + MbUb = MaVa + MaVa
Substituting values;
(0.08 kg * 0.5 m/s) + (0.05 kg * 0 m/s) = (0.08 kg * −0.1 m/s) + (0.05 kg * v)
0.4 = -0.008 + 0.05v
v = 8.16 m/s
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