Question

A neon light is turned on, emitting photons that are 700 nm long and travels at C. What is the EMR’s: a) frequency

b) period and c) what color of visible light is it?

Answer 1

$E=hf$

$E=hf=$ $hc\over \lambda$

Where $E=700nm$

$h=4.14\times 10^{-15}eV.s.$

$hc=1240eV.nm$

a) Frequency(f)

$700 nm=$ $4.14\times 10^{-15}eV.s. \times (f)$

$f=$ $700nm\over 4.14\times 10^{-15}eV.s.$

$=1.690\times 10^{17} nm^{-1}eV.s^{-1}$

b) From the equation$E=$ $hc\over \lambda$

Where $hc=1240eV.nm$

$\therefore \lambda=$ $1240eV. nm\over700nm$ $=1.771eV$

The frequency is therefore $1.771eV$

c) From the $EM$ spectrum, the color of the neon light is Ultraviolet.