Explanation:
Principle focus is the point on the axis of a convex lens, where the parallel rays of light from one side of the lens. meet on other side after refraction. Distance between optical centre to principle focus point is the focal length.
Answer:
Ground-state atom
Explanation:
When an atom is not excited, it is in its ground-state, which we refer as "standard" or "normal" state.
(Hopefully that helped you!)
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Astrophysicist Dr. D
Answer:
A. For every action there is an equal and opposite reaction.
2nd class leaver refers to such leaver in which load lies between effort and fulcrum.In a nut cracker too load is in between effort and fulcrum.Thus, nut cracker is a 2nd class leaver.......