What is the energy of an electromagnetic wave with a frequency of [tex][tex]$8 \times 10^{12}$[/tex] \text{Hz}[/tex]?

A. [tex][tex]$4.2 \times 10^{-22} \text{J}$[/tex][/tex]
B. [tex][tex]$2.4 \times 10^{21} \text{J}$[/tex][/tex]
C. [tex][tex]$1.59 \times 10^{-12} \text{J}$[/tex][/tex]
D. [tex][tex]$5.3 \times 10^{-21} \text{J}$[/tex][/tex]



Answer :

To determine the energy of an electromagnetic wave given its frequency, we can use Planck's equation, which is expressed as:

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

where:
- [tex]\( E \)[/tex] is the energy of the wave,
- [tex]\( h \)[/tex] is Planck's constant, [tex]\( 6.626 \times 10^{-34} \text{ J} \cdot \text{s} \)[/tex],
- [tex]\( f \)[/tex] is the frequency of the wave.

Given data:
- The frequency [tex]\( f \)[/tex] of the wave is [tex]\( 8 \times 10^{12} \text{ Hz} \)[/tex].

Now, we substitute the given values into the equation:

[tex]\[ E = (6.626 \times 10^{-34} \text{ J} \cdot \text{s}) \times (8 \times 10^{12} \text{ Hz}) \][/tex]

When we compute the product:

[tex]\[ E = 8 \times 6.626 \times 10^{-34+12} \][/tex]
[tex]\[ E = 53.008 \times 10^{-22} \][/tex]
[tex]\[ E = 5.3008 \times 10^{-21} \text{ J} \][/tex]

Thus, the energy of the electromagnetic wave is [tex]\( 5.3008 \times 10^{-21} \text{ J} \)[/tex].

Among the given options, the correct answer is:

D. [tex]\( 5.3 \times 10^{-21} \text{ J} \)[/tex]