What is the energy of light with a frequency of [tex]$3 \times 10^9 \, \text{Hz}$[/tex]?

Given:
[tex]h = 6.626 \times 10^{-34} \, \text{J} \cdot \text{s}[/tex]

Calculate:
[tex]E = h \cdot f[/tex]

Where:
[tex]E[/tex] = energy in joules
[tex]h[/tex] = Planck's constant
[tex]f[/tex] = frequency in hertz



Answer :

To find the energy of light with a frequency of [tex]\(3 \times 10^9\)[/tex] Hz, we use the formula for the energy of a photon:

[tex]\[ E = h \cdot f \][/tex]

where:
- [tex]\( E \)[/tex] is the energy of the photon,
- [tex]\( h \)[/tex] is Planck's constant ([tex]\(6.626 \times 10^{-34} \)[/tex] J·s),
- [tex]\( f \)[/tex] is the frequency of the light ([tex]\(3 \times 10^9 \)[/tex] Hz).

Substitute the given values into the formula:

[tex]\[ E = (6.626 \times 10^{-34} \, \text{J·s}) \times (3 \times 10^9 \, \text{Hz}) \][/tex]

Multiplying these values:

[tex]\[ E = 6.626 \times 3 \times 10^{-34 + 9} \][/tex]
[tex]\[ E = 19.878 \times 10^{-25} \][/tex]

This can be written in scientific notation:

[tex]\[ E = 1.9878 \times 10^{-24} \, \text{J} \][/tex]

So, the energy of light with a frequency of [tex]\(3 \times 10^9\)[/tex] Hz is:

[tex]\[ 1.9878 \times 10^{-24} \, \text{J} \][/tex]