Answer:
it is diffuluct for a human because we understand so littlebout how to build a self-sustaining ecosystem that can support us, especially under tight constraints as to its total mass. Simply getting into Earth orbit
Explanation:
That is why it is diffulcut
Electrical > light,sound and thermal
To solve this problem it is necessary to apply the concepts related to the change of Energy in photons and the conservation of energy.
From the theory we could consider that the energy change is subject to

Where
Initial Energy
Energy loses
Replacing we have that


Therefore the Kinetic energy of the electron once it has broken free of the metal surface is 0.8eV
The definition is a nuclear reactor that generates more fissile material than it consumes.