PHYSICS Unit 2 - Electricity (a,b&c) YR 10 IGCSE

Refraction

It’s the bending of light when it travels from one medium to another

Refractive index

A measure of how much a material slows down and bends light.

The formula for refractive index

Refracted= speed of light in air / speed of light in that material

What’s Snell’s law?

Relates the size of angle of refraction to the angle of incidence

Current Flow

positive terminal to negative terminal

Electron Flow

negative terminal to positive terminal

Unit of ameter

ampere (A)

Unit of voltage

Volt (v)

Alternating Current (AC)

an electric current where the flow of charge periodically reverses direction

Direct current

an electric current that flows in only one constant direction ( from positive to negative)

Ohm’s Law

Current is proportional to Voltage

Diode

it allows the current to flow in one direction

What happens if we connect a resistor parallel?

When we connect a resistor parallel the total resistance decreases and the total current increases

What happens if we connect a resistor in series?

When we connect a resistor in series the total resistance increases and the total current decreases.

R=

Resistance

V=

Voltage

I=

Current

Q=

Charge

E=

Energy