## SS: Magnetic field due to current in a straight wire

Movement of electric charge is an underlying cause of magnetism. Hence, an electric current, being a flow of charge, produces a magnetic field. If the current is flowing in a wire, the shape of the magnetic field is dependent on the configuration of the wire. The magnetic field lines produced by a current in a straight wire are in the …

## SS: Wiring a mains plug

Steps: Remove a sufficient amount of outer insulation of the three core wires, Live (brown), Neutral (blue) and Earth (green with yellow). Open the mains plug with a screwdriver and take out the fuse. Remove about 5 mm of the insulation from three wires and twist the copper strands of each wire together. Clamp the edge of the removed outer …

## SS: Loudness and Pitch

The human ear can distinguish two characteristics of sound. These are the loudness and pitch, and each refers to a sensation in the consciousness of the listener.     Loudness It is easy to distinguish among loud and soft sounds. The term loudness of a sound is self-descriptive. It depends primarily on the amplitude of the sound wave. The larger …

## SS: Determining The Speed of Sound In Air

The speed of sound can be calculated with only two measurements: the distance of the sound source from the receiver the time taken for the sound wave to travel that distance   $$speed = \frac{distance \,travelled}{time}$$   Precautions taken to reduce measurement errors: Exchange the positions of the sound source and the measuring device and repeat the experiment. It will …

## SS: Reflection of light

Reflection of light is the abrupt change in the direction of propagation of light rays that strike the boundary between different mediums. Terms used: A ray of light is light from a single point source (normally represented by a long and straight arrow on diagrams. Incident ray is a ray of light striking a surface. Reflected ray is a ray …

## SS: What is light?

Note: This post addresses the question at “GCE O Level” level. In terms of classical wave theory, light is an electromagnetic wave that is capable of passing through free space or through a material medium in the form of varying electric and magnetic fields. In the absence of influence, the wave travels straight. In terms of the modern quantum theory, …

## Reflection And Refraction Of Light (O Level)

This topic covers “Reflection and Refraction of Light” of O Level Physics. (Equivalent to American high school diploma) Sub-topics: What is light? Reflection of light Drawing ray diagrams for plane mirrors Refraction of light Total internal reflection Quiz: Click here for quiz.