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Answer: D) 30</h3>
Angle of incidence always equals angle of reflection. Think of a tennis ball being hit into a wall. The ball will bounce off at the same angle that it approached with. The angles mentioned are formed through the line called the "normal", which is the line perpendicular to the surface.
Isotopes of an element will contain the same number of protons and electrons but will differ in the number of neutrons they contain. In other words, isotopes have the same atomic number because they are the same element but have a different atomic mass because they contain a different number of neutrons
Liter
The Basic Unit for Volume
The liter, which is the basic unit of volume, was originally defined as the volume occupied by 1 kilogram of water, but today it's simply one-thousandth of a cubic meter
BRAINLY PLS