Why do I get darker photos at high shutter speeds?

Yesterday I was asked by a person regarding why he got darker photos every time he  increased the shutter speed.

The answer is simple.
Shutter speed controls the entry of light into your camera. High shutter speed means the camera's shutter is open for a smaller period of time and thereby restricting the amount of light entering the camera.

How to deal with Dust on DSLR Sensors? Photo Soothe

Have you ever noticed those tiny spots on your photos while clicking pictures of the sky or when shooting at narrow apertures? Pretty annoying, right? The sad fact is that DSLR Cameras are dust magnets and you have practically no way to escape dust.

How to check for dust?

1. Before doing this simple test,clean the lens properly with a microfiber cloth , making sure there are not smudges or dirt on the lens.
2. Select a 50mm focal length or longer.
3. Set your camera to Aperture Priority mode