# Physics

### The Cathode Ray Tube

Cathode rays are streams of high speed electrons moving from the cathode. How a Cathode Ray tube works: A low voltage is placed across the filament. Current flows through and it becomes white hot, this heats the cathode. Thermionic emission occurs at the cathode. Electrons are emitted. There is a… Continue Reading →

### The Electron – Physics Chapter Summary

Properties of the Electron It is a particle that orbits the nucleus of an atom. It has a very small mass. It is negatively charged. Charge = e. This is the smallest amount of charge found in nature. It is the indivisible quantity of charge. Millikan first found the value… Continue Reading →

### The Doppler Effect

The Doppler effect is the apparent change in the frequency of the waves due to the motion of the source of the wave or an observer.

### Force, Mass and Momentum – Definitions

Force Force is anything that causes the velocity of an object to change. Force has direction in which it acts – it is a vector quantity. The symbol for force is F. The unit of force is the newton (N). Acceleration of a body is directly proportional to the force causing it, i.e. for… Continue Reading →

### Wave & Wave Motion

What is a wave? A wave is a means of transferring energy through a medium, without any net movementof that medium. Transverse wave: A wave where the direction of vibration is perpendicular to the direction in which the wave travels. e.g. light, waves on a rope, water waves. Longitudinal wave: A wave where the… Continue Reading →

### Introduction to Light – Geometrical Optics

Light is a form of energy that travels away from the source at the speed of about . Reflection Reflection is the bouncing of light off an object. Laws of Reflection of Light The incident ray, the normal at the point of incidence and the reflected ray all lie in the same plane. The angle of incidence is equal to… Continue Reading →

### Differences between series and parallel circuits

A simulation to visualize electron flow through both circuit types.

### Electricity: VOLTs, OHMs and AMPs

What are VOLTs, OHMs & AMPs? Ever wonder what voltage really is? Learn the relationship between voltage, current and resistance in an electric circuit. Ohm’s Law is introduced through a circuit simulation.