What does thrice mean not being mean or anything just saying so I can help with the question
"The equation can be used to calculate the power absorbed by any surface" statement concerning the Stefan-Boltzmann equation is correct.
Answer: Option A
<u>Explanation:</u>
According to Stefan Boltzmann equation, the power radiated by black body radiation source is directly proportionate to the fourth power of temperature of the source. So the radiation transferred is absorbed by another surface and that absorbed power will also be equal to the fourth power of the temperature. So the equation describes the relation of net radiation loss with the change in temperature from hotter temperature to cooler temperature surface.

So this law is application for calculating power absorbed by any surface.
Answer:
Force = 35 N
Explanation:
From Newton's third law of motion, the boy must apply a force greater than the weight of the sled to lift it.
weight of sled = mg
where m is its mass and g the force of gravity on it.
weight of sled = 50 N
Force applied by the boy on the sled = 15 N
Since the force applied on the sled by the boy is lesser than the weight of the sled, then;
Force that the sled exerts on the student = 50 - 15
= 35 N
The force exerted by the sled on the student is 35 N.
The answer is A vaporization