Becuse your weighting with chalk that has pigment
Answer:
50 N.
Explanation:
On top of a horizontal surface, the normal force acting on an object is equivalent to the force of gravity acting on the object. That is:

The mass of the block is 5 kg and the given force due to gravity is 10 N/kg. Substitute and evaluate:

In conclusion, the normal force acting on the block is 50 N.
The FREQUENCY of light remains unchanged once it leaves the source.