Physics

Electrical Power =

current x voltage

Voltage =

current x resistance

Charge =

current x time

Average Speed =

distance / time

Acceleration =

Change in Velocity / Time Taken

Force =

Mass x Acceleration

Pressure Difference =

Height x Density x Gravity

Moment =

Force x Perpendicular Distance from Pivot

Pressure =

Force / Area

Wave Speed =

Frequency x Wavelength

Refractive Index =

Sin (I) / Sin (R)

Sin (Critical angle) =

1 / Refractive Index

Energy Transfer =

Work Done

Work Done =

Force x Distance Moved

Efficiency =

Useful Energy Output / Total Energy Input

Weight =

Mass x Gravity

GPE Potential Energy =

Mass x Gravity x Height

Kinetic Energy =

1/2 x Mass x V^2

Density =

Mass / Volume

Distance Time Graphs

Velocity Time Graphs

Gravity

Force of attraction between all masses

Hookes Law

Extension is directly proportional to force until the spring reaches it's elastic limit

Solar Systems

Galaxy = large collection of stars

Sun = one of many stars

Effects of gravity on planets

Closer you get to a star or a planet the stronger the force of attraction is, so they move quicker in orbit

Types of orbit

Moons and planets have slightly elliptical orbits

Comets orbit the sun, they have very elliptical orbits

Artificial Earth Satellites

Have orbital period of 1 day = geostationary satellites, used for communications

Safety features of Plugs

Filament Lamp

Wire

Resistors

Diodes

Electric Circuit Symbols

Light Dependent Resistor (LDR) Diagram

LDR Explanation

Changes it resistance depending on the amount of light

In bright light the resistance decreases

In dark light the resistance increases

Acts as a light sensor

Thermistor Diagram

Thermistor Explanation

Changes in resistance as temperature changes

In hot condition the resistance decreases

In cool conditions the resistance increases

Acts as temperature detectors

Current

Rate of flow of Charge

Voltage

Driving force which pushes current (Electrical Power)

Resistance

Something which slows down the flow

Circuit Rules

Increase voltage = more current will flow

Increase resistance = less current will flow

Series Circuit

Current the same

Voltage = Voltage of all components

Parallel Circuit

Current = Current of all components

Voltage the same

Transverse Wave Diagram

Longitudinal Wave Diagram

Examples of Transverse Waves

Electromagnetic Waves

Ripple in Water

Examples of Longitudinal Waves

Sound + Ultrasound

Shock Waves

Transverse Wave

Vibrations are at 90° to the direction energy is transferred

Longitudinal Waves

Vibrations are parallel to the direction the wave transfers energy

Wave Info

All waves transfer energy and information without transferring matter

Electromagnetic Waves

Waves have different wavelengths - continuous spectrum

All transverse - Travel at same speed through a vacuum

Diagram of Electromagnetic Waves

Uses of Waves

Radio Waves: Communication

Microwaves: Satellite Communication

Infra-Red Radiation: Heating and monitor temperature

Visible Light: Travel though optical fibres + Photography

Ultraviolet Light: Fluorescent Lamps

X-Rays: See inside things

Gamma Rays: Sterilising medical equipment

Conduction

Process where vibrating particles pass on their kinetic energy

Convection

Particles from their hotter region to the cooler region and take their heat energy with them

Dangers of Microwaves

Yeah human body tissue internally

Dangers of Infra-Red

Skin Burns - Heating effect

Dangers of Ultraviolet

Damage surface cells and causes blindness

Dangers of Gamma

Cell mutation and Tissue damage - can cause cancer

Virtual Image

Light Refraction

Angle of Incidence is less than critical angle

Angle of Incidence is more than critical angle

Angle of Incidence is equal to critical angle

Total internal reflection - Optical fibres

Angle of Incident is always higher than critical angle, light always totally internally reflected - only stops if fibre is to sharp

Sankey Diagram

Power

One Watt = 1 joule of energy transferred per second

Human Hearing Range

20 - 20,000 Hz

Renewable Energy

Wind Farms

Geothermal Energy

Solar Energy

Hydroelectric Power

Brownian Motion

Small particles have a constant, rapid and random movement - small particles can move larger particles - causes pressure

This discovery was proved with the use of pollen grains

Absolute 0 - Kelvin Scale

Absolute 0 - atoms have as little kinetic energy as possible

Absolute 0 = -273°C

50 Kelvin = -223°C

15°C = 288 Kelvin

Uniform Magnetic Field

Loudspeaker

A.C electrical signals - from amplifier - to coil of wire - wrapped around cone

Cone surrounded - permanent magnet - cause a force forwards + backwards

Movements = cone vibrate = sound

Resistance of LDRs and Thermistors Experiments

Measure current at any know/fixed temp

Measure voltage at any known/fixed temp

Vary temp and take new readings

Calculate and draw voltage - current graph

Repete and average

Refraction of light experiment

Place block on sheet of paper

Draw around the block

Turn ray box on and shine beam of light into block

use pencil to mark path of light into and out of block

Remove the block, measure the angle of refraction

Repeat

Measuring speed of sound

Person at one end with a pistol

Other person at a distance a way from the pistol (e.g 500 metres)

Person fires gun

People with stopwatches start time when see the smoke from gun and stop when they hear the bang

Average the time

How temperature effects Gas experiment

Use water bath to vary the temperature

Calculate the volume of air in test tube before heating

Measure volume of air after heating

Use a narrow glass tube with liquid above the air so you can clearly see how it has expanded

Investigating the magnetic field experiment

Place sheet of paper on wooded bench (avoid interaction with other magnets)

Place magnet on sheet of paper

Place plotting compass against the magnet

Mark position of compass needle on the paper with a dot

Move plotting compass so that the tail of the arrow sits where the tip of the arrow was

Repeat process

Join dots

Marsden experiment Diagram

Marsden experiment

Alpha particles were detected as tiny flashes of light on screen

Most alpha particles went straight thought gold foil

A small number deviated as they were repelled

Very few alpha particles bounced back because of the dense nucleus

Conclusion of Marsdens experiment

Most of atom is empty space

Nucleus is small

Nucleus is dense

Nucleus is positive

Flemmings Left hand rule