Just took the test and the answer is <span>C. 1,314,718.
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Answer:
4.71 eV
Explanation:
For an electromagnetic wave with wavelength

the energy of the photons in the wave is given by

where h is the Planck constant and c the speed of light. Therefore, this is the minimum energy that a photon should have in order to extract a photoelectron from the copper surface.
The work function of a metal is the minimum energy required by the incident light in order to extract photoelectrons from the metal's surface. Therefore, the work function corresponds to the energy we found previously. By converting it into electronvolts, we find:

Answer:
15 m/s
Explanation:
Using the law of conservation of energy, potential energy equals kinetic energy hence

Therefore

where g is the acceleration due to gravity, m is the mass of the object, h is the height and v is the speed of the wallet
Taking g as 9.81 then

I believe that the answer is A but correct me if i’m wrong