You need to know the mass number to work it out. I can see you have it but it's not visible on your photo.
Every proton weighs 1 and every neutron weighs 1 so if you know the total mass of the nucleus and the number of protons, then you can do:
Mass Number - Proton Number = Neutron Number
because the rest of the mass (that isn't from the protons) must come from the neutrons. Make sense?
Answer:
(a) λ = 4136 nm → infrared
(b) λ = 413.6 nm → visible light
(c) λ = 41.36 nm → ultraviolet
Explanation:
The wavelength of infrared is on the range of 700 nm to 1000000 nm
The wavelength of visible light is between 400 nm and 700 nm
The wavelength of ultraviolet ray on the range of 10 nm to 400 nm
The wavelength of photon is given by;
E = hf
f is the frequency of the wave = c / λ

Where;
c is the speed of light = 3 x 10⁸ m/s
h is Planck's constant = 6.626 x 10⁻³⁴ J/s
(a) 0.3 eV = 0.3 x 1.602 x 10⁻¹⁹ J

λ = 4136 x 10⁻⁹ m
λ = 4136 nm → infrared
(b) 3.0 eV

λ = 413.6 x 10⁻⁹ m
λ = 413.6 nm →visible light
(c) 30 eV

λ = 41.36 x 10⁻⁹ m
λ = 41.36 nm →ultraviolet
The energy carried by a photon is equal to
(Planck's Konstant) times (the frequency of the photon) .
Planck's konstant is 6.626 x 10⁻³⁴ m²-kg/s (rounded)
Zeroth Law of Thermodynamics, which in turn will mean the heat will transfer between both of them up to the point where they are in thermodynamic equilibrium. So the answer is C.