I am pretty sure this is uranium. it has 140 neutrons.
1 atmospheric pressure = 760.0 mm Hg
Thus 580 mm Hg = (580 mm Hg/(760 mm Hg/atm))
= 0.763 atm
The statement "<span>When an electron is added to a neutral atom of an element to form a negative ion, the resulting change in energy is referred to as the electron potential of that element." is false.
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Answer:
c. The incident light must have at least as much energy as the electron work function
Explanation:
In photoelectric effect, electrons are emitted from a metal surface when a light ray or photon strikes it. An electron either absorbs one whole photon or it absorbs none. After absorbing a photon, an electron either leaves the surface of metal or dissipate its energy within the metal in such a short time interval that it has almost no chance to absorb a second photon. An increase in intensity of light source simply increase the number of photons and thus, the number of electrons, but the energy of electron remains same. However, increase in frequency of light increases the energy of photons and hence, the
energy of electrons too.
Therefore, the energy of photon decides whether the electron shall be emitted or not. The minimum energy required to eject an electron from the metal surface, i.e. to overcome the binding force of the nucleus is called ‘Work Function’
Hence, the correct option is:
<u>c. The incident light must have at least as much energy as the electron work function</u>
The mass of a neutron is:

Since we know its speed, we can calculate the neutron's momentum:

The problem says the photon has the same momentum of the neutron, p. The photon momentum is given by

where h is the Planck constant, and

is the photon wavelength. If we re-arrange the equation and we use the momentum we found before, we can calculate the photon's wavelength:

And since we know the photon travels at speed of light c, we can now calculate the photon frequency: