- Nature of Light:
Light is a form of electromagnetic radiation that is visible to the human eye.
It travels in straight lines and can be represented by rays.
- Speed of Light:
The speed of light in a vacuum is approximately 3 x 10^8 meters per second (m/s).
Light travels at different speeds through different media, such as air, water, or glass.
- Reflection:
Reflection is the bouncing back of light rays from a surface.
The angle of incidence is equal to the angle of reflection, according to the law of reflection.
Examples of reflection include mirrors and polished surfaces.
- Refraction:
Refraction is the bending of light as it passes from one medium to another.
The change in speed causes the light to change direction.
Lenses and prisms demonstrate the phenomenon of refraction.
- Dispersion:
Dispersion is the separation of light into its component colors.
It occurs when light passes through a prism, with different colors having different wavelengths.
- Colors of Light:
White light is a combination of all the colors of the visible spectrum.
The colors of the spectrum are red, orange, yellow, green, blue, indigo, and violet (ROYGBIV).
- Shadows:
Shadows are formed when light is blocked by an opaque object.
The size and shape of a shadow depend on the position and size of the light source.
- Optical Instruments:
Devices like microscopes and telescopes use lenses to form images.
The human eye is also an optical instrument that uses lenses to focus light on the retina.
- Light as a Form of Energy:
Light carries energy and can do work.
Solar cells convert light energy into electrical energy.
- Vision:
The human eye is an organ that allows us to perceive light and color.
The cornea and lens in the eye focus light onto the retina, where it forms an image.
These are some fundamental concepts related to light that are often covered in a class 10 science curriculum. Understanding these principles helps in explaining various optical phenomena and the functioning of optical devices.