cbse class 11th ist lesson Physical world

Force

iit entrance- Wavemotion

longitudinal wave


This animation depicts Transverse and Longitudinal waves on a spring.



For transverse waves the disturbance (in this case the displacement of the slinky) is PERPENDICULAR to the direction the wave is moving (in this case along the slinky). For Longitudinal waves the disturbance is ALONG the direction the wave is moving. In some materials these two waves go at different speeds, and in fluids (liquids or gases) transverse sound waves don't go at all! (This is important for earthquake vibrations going through the earth's core).

A transverse wave is created by a disturbance that is perpendicular to the direction the wave will travel.


A longitudinal wave is created by a disturbance that is along the direction the wave will travel.




Physics: Transverse vs. longitudinal waves. Wave graphs. Velocity (v) versus frequency (f); frequency (f) versus angular frequency (ω)

Human eye and the colourful world

Eye and Lens

Eye

Light , Reflection and Refraction

Refraction





When a ray of light reach the boundary between two different substances, some light is reflected, and some light is refracted. The semi-cylindrical piece of glass has a higher index of refraction.

Rainbow




Light refraction and reflection


Concave lens - physics experiment


Lens that possesses at least one surface that curves inwards. It is a diverging lens, spreading out those light rays that have been refracted through it. A concave lens is thinner at its centre than at its edges, and is used to correct short-sightedness (myopia).

Converging lenses a beginners guide for A level



Lenses

Magnetic effects

Magnetic effects



Magnetism 2


Electricity & Magnetism Hand Rules (part one)



What is the magnetic field?


Origin of Earth's Magnetic Field


Direct current electric motor