EOY 10 EXAMS W/YR9 Stuff

Refraction is

Refraction is

when light waves change direction when they pass from one medium to another

Waves travel

at different speeds through different densities

Higher density =

slower wave

Reflection- Angle of incidence=

angle of reflection

3 primary colours of light

red blue green

Red + Blue =

Magenta

Red + Green =

Yellow

Blue + Green =

Cyan

Blue + Green + Red =

White

why does a white shirt look white

because it reflects all colors of light

why does a red shirt look red

because it reflects the red light and absorbs the green and blue light

why does a green shirt look green

Because it absorbs red and blue light and reflects green light

why does a black blazer look black

because it absorbs all light

the 2 types of wave

Transverse, longitudinal

Examples of transverse waves include

Light waves, radio waves

Examples of longitudinal waves include

Sound waves, seismic P waves

the wave equation

Wave speed = frequency X wavelength

Frequency

How many whole waves in a second

Amplitude

is the distance from the centre line (or the still position) to the top of a crest or to the bottom of a trough .

Wavelength

The wavelength of a wave is the distance between two waves

A light wave bend towards the normal when

When light passes from a less dense to a more dense substance, (for example passing from air into water)

a light wave bends away from the normal when

When light passes from a more dense to a less dense substance,

magnification =

image height

object height

Types of energy stores

thermal kinetic nuclear chemical gravitational elastic electrostatic magnetic

energy transferes are

mechanisms which allow energy to be moved from one location to another

Weight =

mass X gravity

Mass

is a measure of how much of an object there is and how mard is it to accelerate

Force

mg

GPE

mgh

work =

force X distance

Kinetic energy

½ mv²

Hookes law

The extension of a spring is directly proportional through the origin to the force applied, provided irs limit of proportionality is not exceeded

Hookes law equation

F = K X e

K=spring constant in N/m

Power =

work/time

Power also equals

Energy transfered/time

efficency =

useful power/total power input

When a current floes through a wire

a magnetic field is created around it

aNticlockwise

North

clockwise

south

LEFT hand grip rule

Thumb-Force , second-field, third-current

The motor effect

when a current flows through a magnetic field it will experience a force and it will move

Why do we get movement WITH THE MOTOR EFFECT

A CURRENT CARRYING WIRE WILL HAVE A MAGNETIC FEILD AROUD IT. THIS FEILD WILL INTERACT WITH THE MAGNETS AND BE PUSHED OUT OF THE FEILLD

The biggest effect will be when

the current and field are at right angled to each other

If the current and field are parallel there will be

no force

The electric bell

the current flows from the electromagnet because there is a complete circuit. This causes the iron core to become magnet and it attracts the soft iron armature this makes the hammer hit the gong.

The motor effect 3

A wire carrying a current creates a magnetic field . This can interact with another magnetic field, causing a force that pushes the wire at right angles.

An electro magnet

\n

An electro magnet is a temporary magnet made by winding wire around an iron core.

Charge=

current x time

like charges

Different charges

REPEL

ATTRACT

Radial field

As you move away from the sphere the feild gets weaker

negitive sphere, - out + in

plus sphere, -in +out

Charge is measured in

Coulombs

Current is the

measure of the movement of charge and is measured in amps (coulombs per second)

Ametre

measures how much charge is moving around a current

Voltmetre

measure of p.d this is the measure of energy a cells gives to the charge§

Resistor

Resistance is a measure of hoe hard it is for current to flow through a component , measured in ohms.

V=

IR

IV Graph filament bulb

Diode

Light dependant resistor

As the light intensity increases the resistance falls

IV experiment

Variable resistor, bulb, ammeter in series, voltmeter in parallel

Change current and measure the P.d

Thermosistors

As temprature increases resistance falls

Ohmic resistor

LED graph

Series more bulbs=

more resistance

Parallel more bulbs =

more current and and less resistance

Resistance in series and NO. of bulbs

Graph goes up

Not straight because bulbs are less bright and cold.

Resistance in parallel and NO. of bulbs

Series

resisatance can be added, current same everywhere, potential differences add to supply.

Parallel

Potential difference = same for all resistors, total current = all current added together.

Parallel Rtotal =

V/I total.

Using a LDR to measure light intensity

V =

E/Q

Energy transfered =

Charge x P.D

P=

E/T

I=

Q/T

Power =

I² x R

density =

mass/ volume

Density Eureka Can experiment

use balace to measure mass, submerge object into eureka can with water in it with a measuring cylinder underneath the spout, record the volume of water in the cylinder, work out density with d=m/v formula

Density of a liqiud

place measuring cylinder on balance and zero it. pour 10ml of liquid into cylinder and measure the mass, pour another 10ml and record total volume and mass, repeat process until measuring glass full, for each measurement find density, take an average, to get an accurate density.

Ray Box Experiment

Place transparent block on paper, trace around it, Use ray box to shine laser through it, trace incident ray band mark where it emerges, remove block and join up lines, measure anglw of incidence and refraction, repeat with other materials,

Types of lenses

Concave/ diverging and Convex/ converging

Uses for concave lenses

telescopes, binoculars,

Uses for convex lenses

microscopes, camera

2 types of magnet

permanant and induced,

field line arrows go

north to south

induced magnets are only magnetised

when in another magnetic field

what is an electromagnet

a metal core with a coil of wire around it and current flowing through it

Solenoid

coil of wire

How to increase power of elecromagnet

increase coils and increase current flowing through it

Uses of electromagnets

scrap yards, in circuits,

How loudspeakers work

https://docs.google.com/document/d/11-d1PgEV2gBoyOo4TOMmnD1k0-LI1l0r-bjeQ3OHw1Q/edit

in a moving-coil loudspeaker a varying current has a m.f, the current’s changing m.f in the coil interacts with the permanent m.f, as the current changes direction the force on the coil changes direction, the coil vibrates and these vibrations are amplified by the cone or diaphram

Order of EM waves

radio, micro, infrared, visible, ultra violet, x rays, gamma,

Ripple tank

set up ripple tank make sure rod touches the water, turn on increasing frequency until low frequency waves can be seen, distance between each wave = one wavelength, measure waves that are 10 wavelengths apart, divide distance by 10,

range of sound

20Hz- 20kHz

Sound is causes by

objects vibrating

ultrasound

UV waves can pass through the body but when it reaches 2 different medias some of the waves are reflected back.

Ultrasound uses

babies, finding cracks, unterwater exploration.

Ultrasound unterwater question

distance = speed x time, halve distance

radio waves made

by oscillating charges