Answer
B. X
A plate of glass or metal ruled with very close parallel lines, producing a spectrum by diffraction and interference of light.
diffraction grating is an optical component that splits and diffracts light into several beams travelling in different directions. The light emerges with its colours separated.
It's an electric motor that converts electric energy into Mechanical energy
Well idk if this helps but the formula to solve acceleration is
a=F/m=(100kg)=1.0m/s 2
The intensity of the magnetic force F experienced by a charge q moving with speed v in a magnetic field of intensity B is equal to

where

is the angle between the directions of v and B.
1) Re-arranging the previous formula, we can calculate the value of the magnetic field intensity. The charge is

. In this case, v and B are perpendicular, so

, therefore we have:

2) In this second case, the angle between v and B is

. The charge is now

, and the magnetic field is the one we found in the previous part, B=2.8 T, so we can find the intensity of the force experienced by this second charge:
Answer:
D. It has been demonstrated to be without exception under certain stated conditions.
Explanation:
A principle is simply a proposition based on some results from some experiments. A principle becomes a law when it gains strength. That is when other scientists support and back it.
A scientific law is a statement that describes a natural phenomenon and is not contradicted by repeated experiments over the time.
Sir Isaac Newton's law of gravitation stated "A gravitational force exists between all objects in the universe. This force is directly proportional to the masses of the two objects and inversely proportional to the distance between them."
His law explained that every body in the universe attracts every other body. It explained that it is not just Earth that pulls us towards it. But even sun and moon has their own gravitational pull and so does all other objects. It is just that the Gravitational pull of some objects is negligible.
Newton's law of Gravitation is considered a universal law because it is applicable to almost all the bodies in the universe and is demonstrated to be correct for them under certain conditions.