<u>Answer:</u>
<u>For A:</u> The wavelength of the light is 
<u>For B:</u> The number of photons per joule is 
<u>For C:</u> The binding energy of a metal is 1.197 eV.
<u>Explanation:</u>
The equation used to calculate the energy of a photon follows:
......(1)
where,
E = energy of a photon
h = Planck's constant = 
c = speed of light = 
= wavelength
Given values:
E = 
Putting values in equation 1, we get:

Converting the wavelength into nanometers, the conversion factor used is:

So, 
Hence, the wavelength of the light is 
Given values:

Putting values in equation 1, we get:

To calculate the number of photons, we use the equation:

Total energy = 1 J
Energy of a photon = 
Putting values in the above equation:

Hence, the number of photons per joule is 
To calculate the binding energy of a metal, we use the equation:
.....(2)
E = Total energy
K = Kinetic energy of a photon
B = Binding energy of metal
Converting the energy from joules to eV, the conversion factor used is:

Using the above conversion factor:

Putting values in equation 2:

Hence, the binding energy of a metal is 1.197 eV.