class 10

When light travels from one medium to another, the speed of its propagation changes, as a result, it ‘bends’ or is ‘refracted’. Now when light passes through a prism, it is refracted towards the base of the triangle.

When a ray of light travels from one medium to another medium, it changes its path because it has different speed in different media. This phenomenon is called refraction of light.

A tiny current loop act's as a tiny magnet technically called a magnetic dipole. The strength of that tiny magnet, the magnetic dipole moment m, is given by m = NIA, giving the units - Ampere meter square. The magnetic dipole moment is a vector quantity and its direction is given by the right-hand thumb rule. Magnetic dipoles are different than electric dipoles in that, there are no magnetic monopoles, only dipoles.

This demo shows that the direction of an induced current is always such as to oppose the change in the circuit or the magnetic field that produces it.

Paper helicopters spin because of the earth’s gravity, lift, and configuration of the rotors. When dropped, the helicopter’s mass experiences gravity, and it naturally falls to the floor which causes paper blades to bend slightly upward due to lift. The lift force of the air pushes on each of the blades equally but in opposite directions, horizontally and vertically. As a result of the horizontal equal, opposite, and offset forces, the helicopter spins around as it descends.