Question

The line spectrum of lithium has a red line at 670.8 nm. Calculate the energy of a photon with this wavelength.

Answer 1

3x10^8 / (670.8 * 10^-9) =4.47x10^14 Hz 4.47x10^14 Hz multiplied by plank's constant = 2.9634x10^-19

2.96 x10-19 J

Answer 2

Answer: The energy of the photon having the given wavelength is
`2.96* 10^(-19)J`

Step-by-step explanation:

We are given:

Wavelength of microwave =
`670.8nm=670.8* 10^(-9)m` (Conversion factor:
`1m=10^9nm` )

To calculate the energy of one photon, we use Planck's equation, which is:

`E=(hc)/(\lambda)`

where,

h = Planck's constant =
`6.625* 10^(-34)J.s`

c = speed of light =
`3* 10^8m/s`

`\lambda` = wavelength =
`670.8* 10^(-9)m`

Putting values in above equation, we get:

`E=(6.625* 10^(-34)J.s* 3* 10^8m/s)/(670.8* 10^(-9)m)\\\\E=2.96* 10^(-19)J`

Hence, the energy of the photon having the given wavelength is
`2.96* 10^(-19)J`