Question

Infrared radiation has wavelength 4 × 10–5 m. What is the frequency of the radiation?


2.5 × 1010 Hz


5 × 1011 Hz


1.2 × 1013 Hz


7.5 × 1012 Hz

Answer 1

Answer:

7.5x1012

Explanation:

Hope it's help you & try to understand equation

Answer 2

Answer:

The frequency, $\nu$, of the infrared radiation measured is $7.5\times 10^{12}Hz$.

Therefore, option d) $7.5\times 10^{12}Hz$ is correct.

Explanation:

Data given,

The given wavelength of infrared radiation, $\lambda$ = $4\times 10^{-5} m$

At $4\times 10^{-5} m$ wavelength, the frequency of infrared radiation, $\nu$ =?

As we know,

• The speed of the light ( c ) is the product of the wavelength ( $\lambda$ ) and the frequency ( $\nu$ ) of the given radiation.

Thus,

• $c = \lambda \nu$      -------equation$(1)$

As we know, the light's speed is $3\times 10^{8} m/s$.

After putting the given value of $\lambda$ and the value of light's speed in the equation $(1)$, we get:

• $3\times 10^{8} = 4\times 10^{-5}\times \nu$
• $\nu = \frac{3\times 10^{8} }{4\times 10^{-5} }$
• $\nu = 7.5\times 10^{12}Hz$

Hence, the frequency of the infrared radiation, $\nu$ = $7.5\times 10^{12}Hz$.