Question

the frequency of a given region of the electromagnetic spectrum is more than 3 x 10^19HZ. note that the speed of light is 2.998 x 10^8 m/s. which waves are found in this region ?

Answer 1

Answer: X-rays are found in the given region.

Explanation:

To calculate the wavelength of light, we use the equation:

$\lambda=\frac{c}{\nu}$

where,

$\lambda$ = wavelength of the light

c = speed of light = $2.998\times 10^8m/s$

$\nu$ = frequency of light = $3\times 10^{19}s^{-1}$

From above, we know that frequency is inversely related to wavelength of light. Thus, the region having frequency more than the given one will have wavelength less than the calculated one.

Putting the values in above equation, we get:

$\lambda=\frac{2.998\times 10^8m/s}{3\times 10^{19}s^{-1}}=9.99\times 10^{-12}m=9.99\times 10^{-3}nm$ 

(Conversion factor:  $1m=10^9nm$  )

The region where wavelength is less than $9.99\times 10^{-3}nm$ is X-rays.

Hence, X-rays are found in the given region.

Answer 2

To solve this problem, You need to look up a picture/diagram of the electromagnetic spectrum. This will have the wave regions listed as well as frequencies and wavelength.
Wavelength is distance/length of one wave, which can be calculated using frequency (hz = s^-1) and the speed of light.
2.998 x 10^8 m/s ÷ 3 x 10^19 s^-1 = 9.99 x 10^-12 m

The Frequency given falls in between X-rays and Gamma rays. The wavelength however; is in the Gama ray region.