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

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



Answer :

To find the energy of an electromagnetic wave given its frequency, we can use Planck's equation:

[tex]\[ E = hf \][/tex]

where:
- [tex]\( E \)[/tex] is the energy of the photon,
- [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 electromagnetic wave.

Given the frequency [tex]\( f = 8 \times 10^{12} \text{ Hz} \)[/tex], we can substitute the values into the equation:

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

Multiplying these values together:

[tex]\[ E = 5.3008 \times 10^{-21} \text{ J} \][/tex]

Thus, the energy of the electromagnetic wave is:

[tex]\[ E = 5.3008 \times 10^{-21} \text{ J} \][/tex]

The closest option to this value is:

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

Therefore, the correct answer is:

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