Answer:
<h3>Standard unit is a standard measure that remains the same whenever, wherever and by whoever it is used. eg: The standard unit of time is second.</h3>
78.4 joules is the energy of a 4 kg apple that is sitting on a 2 m high tree branch.
<u>Explanation:
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When an apple falls to the ground from a tree, its positional energy (stored as potential gravitational energy) turns into kinetic energy, during a fall. Chemical potential energy is chemical energy because it is food and potential energy as it can still have ability to move. So, in the given case, kinetic energy is zero.
To find potential energy, the formula would be

Where, given
m – Mass – 4 kg
(Known value)
h – Height - 2 m
Substitute these values, we get

C. Nuclear power does not produce any form of pollution.
concentration is the ratio of solute in a solution to either solvent or total solution.