Physics

Scattering of light, Tyndall effect, blue sky, and red sunset

Scattering of light occurs when light interacts with particles in a medium and is deflected in different directions.
The intensity of scattered light depends on the wavelength of light and the size of the particles.
Shorter wavelengths (blue and violet) are scattered more than longer wavelengths (red and yellow).
This phenomenon is described by Rayleigh scattering for small particles.
When particles are compar

Dispersion is the phenomenon where white light splits into its constituent colors when it passes through a prism.
It occurs due to the variation in the refractive index of the material for different wavelengths of light.
The order of colors in the visible spectrum is: Violet, Indigo, Blue, Green, Yellow, Orange, Red (VIBGYOR).
Isaac Newton was the first to demonstrate dispersion using a glass prism.
The angle of deviation is

The human eye is a natural optical instrument that enables vision.
It consists of components like the cornea, lens, retina, iris, and optic nerve.
The lens focuses light onto the retina, where the image is formed.
The ability to focus on objects at varying distances is due to the process of accommodation.
Common defects include:
- Myopia (short-sightedness): Corrected with concave lenses.

The lens formula is given by 1/f = 1/v - 1/u, where:
- f: Focal length of the lens
- v: Image distance
- u: Object distance
This formula is applicable for both convex and concave lenses.
The sign convention depends on the position of the object and the nature of the lens.
Convex lenses (converging lenses) have positive focal lengths, while concave lenses (diverging

A mirror is a reflective surface that forms images by reflecting light.
Plane mirrors produce upright, virtual images with the same size as the object.
Curved mirrors are classified as concave or convex based on the direction of curvature.

The speed of light in a vacuum is the fastest possible speed in the universe, approximately 3 × 10⁸ m/s.
In any other medium, light travels slower than it does in a vacuum due to interactions with the medium's particles.
The ratio of the speed of light in a vacuum to its speed in a medium gives the refractive index of the medium (n = c/v).
A higher refractive index indicates a slower speed of light in that medium.

Reflection is the phenomenon where light bounces back from a surface.
The law of reflection states that the angle of incidence (i) is equal to the angle of reflection (r).
Reflection occurs at the boundary of two mediums, such as air and a mirror.
Reflection can be regular (on smooth surfaces) or diffuse (on rough surfaces).
Plane mirrors produce virtual, upright, and laterally inverted images.
Spheric

Musical instruments produce sound through the vibration of strings, air columns, or membranes.
The pitch of a sound is determined by the frequency of vibrations in the instrument.
String instruments like the violin and guitar create sound through vibrating strings.
The length, tension, and thickness of the string influence the pitch of the sound.
Wind instruments, such as flutes and trumpets,

Ultrasonics refers to sound waves with frequencies above the human hearing range, typically greater than 20,000 Hz.
Ultrasonic waves have short wavelengths, allowing them to be highly directional.
These waves are used in medical imaging, including ultrasound scans for monitoring pregnancy and diagnosing medical conditions.
In industrial applications, ultrasonics is employed for cleaning delicate objects and in welding plastics.
Ultras

The Doppler effect refers to the apparent change in the frequency or wavelength of a wave observed by an observer moving relative to the source of the wave.
It occurs in all types of waves, including sound, light, and water waves.
The effect is commonly experienced with sound waves, such as when an ambulance siren changes pitch as it passes by.