(A) Calculate the wavelength (in nm) of light with energy 1.89 × 10–20 J per photon, (b) For light of wavelength 410 nm, calculate the number of photons per joule, (c) Determine the binding energy (in eV) of a metal if the kinetic energy possessed by an ejected electron [using one of the photons in part (b)] is 2.93 × 10–19 J.

For A: The wavelength of the light is

For B: The number of photons per joule is

For C: The binding energy of a metal is 1.197 eV.

Explanation:

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.

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.