The equation for photon energy, E, is E=hc/λ where h = 6.626×10−34 J⋅s (Planck's constant) and c = 2.99×108 m/s (the speed of light).

What is the wavelength, λ, of a photon that has an energy of E = 3.92×10−19 J ?

The wavelength, λ, of a photon that has an energy of E = 3.92×10⁻¹⁹ J is 5.054*10⁻⁷ m

Explanation:

The wavelength is defined for every periodic wave, that is, for the type of wave that repeats itself with exactly the same shape every given interval of time. It is the distance between two points from which the wave repeats.

Radiation is the emission, propagation and transfer of energy in any medium in the form of electromagnetic waves or particles.

The energy carried by electromagnetic radiation travels by waves. This energy is transmitted grouped in small "quanta" of energy called photons. The energy of a photon is measured in Joules (J) and is

Being:

and replacing:

you get:

wavelength= 5.054*10⁻⁷ m

The wavelength, λ, of a photon that has an energy of E = 3.92×10⁻¹⁹ J is 5.054*10⁻⁷ m

d: the voltage of the secondary coil is less than that of the primary coil.

im not suree sorry if wrong