Page 1 of 1

### Intensity VS Frequency

Posted: Tue Oct 01, 2019 12:47 am
Does higher frequency always mean shorter wavelength (and lower frequency always mean longer wavelength)? Also, when the intensity of light is increased, what exactly is being increased? I thought that changing the intensity of light altered the frequency / wavelength.

### Re: Intensity VS Frequency

Posted: Tue Oct 01, 2019 10:58 am
Frequency is the number of cycles per second. Intensity is increasing the moles of electrons (so having more of them).

Light has both wavelike and particle properties. This was shown in the photoelectric effect because when we increased intensity, there was no effect on the amount of electrons being ejected because none of them had enough energy. But when we shortened the wavelength, it did eject electrons. Therefore, the following equation was concluded: frequency = speed of light/wavelength. And, if we derive this further: Energy = h x frequency = (h x speed of light)/wavelength; showing that energy of a photon is dependent on wavelength.

So if we have a shorter wavelength, we get a higher frequency and vice versa since it is an inverse relationship.

### Re: Intensity VS Frequency

Posted: Wed Oct 02, 2019 3:41 pm
The intensity of light is related to the amplitude, which is independent from wavelength and frequency. Therefore changing the intensity of light wouldn't alter the frequency/wavelength but rather the amplitude. The amplitude of a light's wave indicates the intensity or brightness of the light and basically tells you how much energy the wave carries if im not mistaken.

### Re: Intensity VS Frequency

Posted: Wed Oct 02, 2019 4:03 pm
a shorter wavelength has a higher frequency (meaning that the amount of oscillations per time period is higher)
a longer wavelength has a lower frequency (meaning that the amount of of oscillations per time period is lower)

For example: blue light frequency is 6.4 x 10^ 14 Hz while red light frequency is 4.3 x 10^14 Hz, meaning that blue light is shorter than red light because it has a higher frequency than red light. I suggest you take a look at the light spectrum to get a better feeling for this; I found that this helped me to better visualize this concept.