how to calculate the energy of the ultraviolet ray if the wavelenght is 150mm?

Answer 1

First we work out the frequency from -:

Speed of Light = Frequency x Wavelength

3 x 10^8 = Frequency x 150x10^-3

Frequency = 3 x 10^8 / 150 x 10^-3 = 2 x 10^9 Hertz

Now for Energy-:

Energy = Planck Constant x Frequency
Energy = 6.63 x 10^-34 x 2 x 10^9 = 1.326 x 10^-24 Joules

or 8.2875 Electron Volts (eV)

Answer 2

I suppose you have done a mistake. For the unltraviolet ray the wavalength is in nm

you have E = hc/wavelength

h = 6.6210^-34 ; c= 310^8m/s ; 150 nm = 150*10-9m

E = 6.6210^-34 * 310^8/15010^-9=1.324 10¨-18J

Answer 3

E = hc/wavelength

= (6.626*10-34 J*sec*3*108m/s)/
(150mm)*(m/1000mm)

1.324 * 10-24 J

Answer 4

E=hc/lambda where E is energy, h is the Planck constant, c is the speed of light in vacuo and lambda is wavelength.

Putting these values in gives

E = 1.326x10^-24J or E = 8.2875x10^-6 eV