<span>B. It stays the same</span>
Data Analysis and Conclusion
When a light wave strikes an object, it can be absorbed, reflected, or refracted by the object. All objects have a degree of reflection and absorption. ... In the natural world, light can also be transmitted by an object. That is, light can pass through an object with no effect (an x-ray, for example).
As per the question the mass of the boy is 50 kg.
The boy sits on a chair.
We are asked to calculate the force exerted by the boy on the chair at sea level.
The force exerted by boy on the chair while sitting on it is nothing else except the force of gravity of earth i.e the weight of the body .The direction of that force is vertically downward.
At sea level the acceleration due to gravity g = 9.8 m/s^2
Hence the weight of the boy
[m is the mass of the body]
we have m = 50 kg.
Hence w = 50 kg ×9.8 m/s^2
=490 N kg m/s^2
= 490 N
Here newton [N] is the unit of force.