To determine the wavelength [tex]\(\lambda\)[/tex] of an electromagnetic wave, we can use the equation:
[tex]\[\lambda = \frac{v}{f}\][/tex]
where [tex]\( v \)[/tex] is the speed of light and [tex]\( f \)[/tex] is the frequency of the wave.
Given:
- Frequency, [tex]\( f = 4.0 \times 10^{18} \)[/tex] Hz
- Speed of light, [tex]\( v = 3.0 \times 10^8 \)[/tex] m/s
We can substitute these values into the equation to find the wavelength.
[tex]\[\lambda = \frac{v}{f} = \frac{3.0 \times 10^8 \, \text{m/s}}{4.0 \times 10^{18} \, \text{Hz}}\][/tex]
When we perform the division:
[tex]\[\lambda = 7.5 \times 10^{-11} \, \text{m}\][/tex]
Thus, the wavelength of the electromagnetic wave is [tex]\( 7.5 \times 10^{-11} \, \text{m} \)[/tex].
Therefore, the correct answer is:
A. [tex]\( 7.5 \times 10^{-11} \, \text{m} \)[/tex]
