Yr 11 Electricity and Magnetism – Part 1 Electrostatics Experiments- Answers

PART A: CHARGED BALLOON

Inquiry Question:  How is the static electricity made and how a charged balloon interacts with

pieces of paper, someone’s hair, a stream of water and what happens when it brought next to a wall.?

AIM: To investigate the interaction of a charged balloon with various objects (charged and uncharged

PART A (CHARGED BALLOON)

 

  1. Rub one of the balloons with the cloth. Observe what happens when you place the rubbed side of the balloon which is now charged, close to the pieces of paper, your friend’s hair, a thin stream of water and next to the wall.

Record your observations below.

 

Activity: Place rubbed balloon close to Observation
a.    to pieces of paper. Balloon attracts the pieces of paper.
b.    your friend’s hair, Balloon attracts hair and the hair repels each other.
c.    a thin stream of water. Thin stream of water attracts/bends towards balloon.
d.    Next to the wall. Balloon is attracted to the wall.

 

PART B (CHARGED EBONITE AND PERSPEX RODS)

  1. Rub the ebonite rod with the cloth (flannel). Observe what happens when you place the rubbed rod which is now charged, close to the paper and a thin stream of water.

Record your observations below.

Activity: Place rubbed ebonite close to Observation
a.    to pieces of paper. Balloon attracts the pieces of paper.
b.    your friend’s hair, Balloon attracts hair and the hair repels each other.
c.    a thin stream of water. Thin stream of water attracts/bends towards balloon.

 

 

  1. Rub the Perspex rod with the cloth (flannel). Observe what happens when you place the rubbed rod which is now charged, close to the paper and a thin stream of water.

Record your observations below.

 

Activity: Place rubbed Perspex close to Observation
a.    to pieces of paper. Balloon attracts the pieces of paper.
b.    your friend’s hair, Balloon attracts hair and the hair repels each other.
c.    a thin stream of water. Thin stream of water attracts/bends towards balloon.

 

 

  1. Stick one of the charged rods onto the watch glass with Blu Tack so that it rotates freely and observe what happens when other charged rods are brought close to but not touching the charged rod.

Record your observations below.

Same charged rods repels and opposite charged rods attracts

 

  1. Write a conclusion for your experiments:

 

Experiments have shown that

  • Like signed charges repel each other (Coulomb law of electrostatics)
  • Unlike signed charges attract each other (Coulomb law of electrostatics)
  • Charged object attracts an uncharged objects.
  • For an isolated system, the net charge of the system remains constant
  • Charge Conservation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

An electroscope is a very simple instrument that is used to detect the presence and magnitude of electric charge on a body such as static electricity. The type of electroscope detailed in this experiment is called a pith-ball electroscope. It was invented in 1754 by John Canton. The ball was originally made out of a spongy plant material called pith. Any lightweight nonconductive material, such as aluminum foil, can work as a pith ball. The pith ball is charged by touching it to a charged object. Since the ball is nonconductive and the electrons are not free to leave the atoms and move around the ball, when the charged ball is near a positively charged body, or source, the negatively charged electrons are attracted to it and the ball moves towards the source. Conversely, a negatively charged source will repel the electrons, and therefore the ball. Electroscopes can also be used to detect ionizing radiation. In this case, the radiation ionizes the air to be more positively or negatively charged depending on the type of radiation, and the ball will either be attracted or repelled by the source. This is how electroscopes can be used for detecting x-rays, cosmic rays, and radiation from radioactive material.

Year 11 Physics – Electricity and Electromagnetism- Static Electricity

RUBBING YOUR SHOES ON CARPET CAN “ZAP” YOU. WHY?

 STATIC ELECTRICITY

The ancient Greeks discovered that rubbing amber with fur or other objects, it could pick up things like feathers! They may have discovered electricity. Electricity comes from the Greek word elector, which means ‘beaming sun’. This name came about because amber had a rich yellow glow in the sunlight.

 Have you had any of these experiences?

  • You walk to the tap to have a drink. Zap~
  • You put a jacket over your nylon team jumper. Zap~
  • Here comes mum in the car, and you touch the car door handle. Zap~
  • Even at home the carpet can zap you~

 

Static electricity is made when materials rub together. The more they rub together, the more electricity is made. This means bigger sparks. When you rub or brush a rod with a cloth, you rub off electrons. Having too many electrons makes a negative charge, and having too few electrons makes a positive charge. A spark is formed when electrons jump from where there are too many electrons to where there are too few.

The study of static electricity forces is called electrostatics. An uncharged plastic rod has an equal number of positive and negative charges. The negative charges are called electrons. Because they are at the edge of the atoms, electrons are easy to rub off. When you rub or brush a rod with a cloth, you rub off electrons. Sometimes the electrons are rubbed off the rod onto the cloth. And sometimes the electrons are rubbed off the cloth onto the rod.

Static electricity occurs with many non-metal materials. There is an electric field around objects which have an electric charge.

Year 11 Physics – Electricity and Magnetism

Static Electricity – What you already know – from Middle school

attract Two objects moved towards each other due to a force. Two like charges attract.
battery Power source that provides energy in a circuit and it is made up of two or more cells.
Bulb An electrical component which transform electrical energy into light energy. Also called a globe or lamp.
cell One unit of energy source which uses chemical reactions to produce current.
circuit A path for the electric current to flow
closed circuit A complete path for the current to flow out of the positive terminal of the battery and back to the negative terminal of the battery.

 

Coulomb’s law Is used to explain the relationship between electrical force and the two charges.

Coulomb’s law states that the electrical force between two charged objects is directly proportional to the product of the quantity of charge on the objects and inversely proportional to the square of the separation distance between the two objects.

electrical conductor A material that allows electricity to flow through it, e.g. metals
electrical insulator A material which does not allow electricity to flow through it, e.g. plastic
electric permittivity Has a value of  is 8.854 x 10-12 A2 s4 kg-1 m-3.

Is the measure of a material’s ability to store an electric field

electromotive force Is the electrical intensity or “pressure”  of potential difference across terminals of the electrical energy source such as a battery. This potential difference can drive an electric current if an external circuit is attached to the terminals of the energy source.
electricity Energy that comes from the flow of charged particles.
ferromagnetic  Materials such as iron, cobalt and nickel that are more easily attracted to the poles of the magnet or can be used as to make electromagnet.
magnetic field Region or an area surrounding a magnet where a force acts on magnetic materials.
motor An electrical component which rotates when it is connected to a battery. It transforms electricity energy into kinetic energy.
non – ohmic A conductor which does not obey Ohm’s law, for example, the tungsten filament in the bulb.
Ohm’s law Is the relationship between voltage and current in an ohmic device. V = IR,    where V=potential difference, I= current and R = resistance of material.
ohmic conductor The wires used to join electrical components.
conductor A material that allow current to flow through it. E.g. metals
Electricity supplied for use in homes and businesses.
open circuit A break in a circuit.
parallel circuit A circuit in which electric current flows through more than one paths in a circuit.
repel A force that pushes an object away. Two like changes will repel
permanent magnet A magnet (usually made of steel) that possesses its own permanent magnetic field.
permeability A measure of the ability of a material to permeability to allow  magnetic field to form inside of a medium
potential difference The difference in electric potential between two points which will then cause the electrons to flow.
power source A source of electrical power, can be a battery or mains.
repel A force that pushes an object away. Two like changes will repel.
series circuit A simple circular path in which electric current flows only one way through each part.
solenoid A cylindrical coil of wire which when current passes through it produces a magnetic field.
static electricity The build-up of electrical charges on a surface, for example, by rubbing your shoes on a carpet.
switch A device which can control the flow of electricity.
symbol A symbol used to represent an electrical component.
terminals The parts of a battery that need to be connected in the circuit.
voltage The amount of potential energy between two points on a circuit. One point has more charge than another. This difference in charge between the two points is called the voltage.

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Physics NEW (Implemented from 2018)

Physics NEW (Implemented from 2018)

View course

Supporting documents:

Course No:

  • 11310 Year 11 Physics
  • 15330 Year 12 Physics.

2 units for Year 11 (Preliminary) and Year 12 (HSC).

Year 11 Course Structure and Requirements

Year 11 course

 

(120 hours)

Working Scientifically Skills Modules Indicative hours Depth studies
Module 1

Kinematics

60 *15 hours

in Modules 1–4

Module 2

Dynamics

Module 3

Waves and Thermodynamics

60
Module 4

Electricity and Magnetism

 

*15 hours must be allocated to depth studies within the 120 indicative course hours.

Year 12 Course Structure and Requirements

Year 12 course

 

(120 hours)

Working Scientifically Skills Modules Indicative hours Depth studies
Module 5

Advanced Mechanics

60 *15 hours

in Modules 5–8

Module 6

Electromagnetism

Module 7

The Nature of Light

60
Module 8

From the Universe to the Atom

 

*15 hours must be allocated to depth studies within the 120 indicative course hours.

 

Year 11 Physics Waves Rays Model of light – (B) Experiment using Lenses

HOW TO WRITE INQUIRY QUESTION AND DRAW RAY DIAGRAMS FOR EXPERIMENTS USING LENSES?

Syllabus DOT POINT:

3.4a. Conduct a practical investigation to analyse the formation of images in mirrors and lenses via reflection and refraction using the ray model of light (ACSPH075)  

EXPERIMENT (A) Physics Practical Investigation: (B) Refraction of rays through convex and concave lenses.

AIM: To analyse the formation of reflected images from convex and concave lenses.

INQUIRY QUESTION: Link inquiry question to the aim of the experiment and write a hypothesis in the form of a question.  Examples of inquiry question are as given below.

  • What are the properties of reflected images formed from convex and concave lenses and how are these images formed? 
  • How are the reflected images in convex and concave lenses formed and what are the properties of these images?
  • How to use ray diagrams to determine the properties of images formed from convex and concave lenses?

What are the characteristics or properties of the reflected image? It is helpful to use SLOT – where:

S – represents the size of the image (same size, magnified or diminished (smaller) compared to the object.

L – represents the location of the image (how far is it from the mirror).

O- represents the orientation of the image (upright or inverted)

T- represents the type of the image (real or virtual). Real images refer to images formed on the same size as the object and can be captured on a screen. Virtual images are formed on the opposite side of the object.

(i) size of the image compared to the actual object (same size or magnified (larger) or diminished (smaller)

(ii) upright

(iii) laterally inverted (left-right reversed)

(iv)real (means the image is formed on the same size of the mirror as the object and can be observed by placing a screen

or virtual  (means the image is formed on the opposite side of the mirror as the object and like see your image behind the mirror).

 

HOW TO DRAW RAY DIAGRAMS CORRECTLY IN A SCIENTIFIC INVESTIGATION?

A – Experiment Using Lenses  – Drawing Ray diagrams and description of image

1.1 Convex Lens

Ray diagrams -Poorly drawn Ray diagrams – correctly drawn Description of image

Characteristics or properties of the image)

Common Mistakes:

  • No arrow (direction) on the refracted ray  
  • The Focal point  not labelled
Comments:

  • Arrow (direction) indicated on refracted ray
  • The Focal point ls correctly labelled
Refer to ray diagram

 

1.2 Concave lens  

 

Ray diagrams -Poorly drawn Ray diagrams – correctly drawn Description of image

Characteristics or properties of the image)

Common Mistakes:

  • Using dotted lines to draw reflected rays.
  • No arrows (direction) on reflected rays
  • Focal point not indicated.
  • Inaccurate drawings of reflected rays leading to inaccurate location of  focal point.
Comments:

  • Arrow (direction) indicated on reflected ray.
  • Correct label for virtual focal point, y.
  • Accurate drawings of reflected rays. Leading to accurate location of focal point.
(i) If the object is placed further than the focal point, the image is:

  • real   
  • magnified if it is more than twice the focal length OR  smaller if between focal length and less than twice the focal length.
  • laterally inverted(left-right reversed)
  • inverted

(ii) If the object is placed closer than the focal  length, the image

  • virtual  
  • Magnified (larger than the original object).  
  • laterally inverted(left-right reversed)
  • inverted

(iii) If the object is placed at the focal  length,

  • virtual  
  • Magnified (larger than the original object).  
  • laterally inverted(left-right reversed)
  • inverted

 

 

 

 

 

Year 11 Physics Waves and Thermodynamics – Rays Model of light – (A) Experiment using Mirrors

HOW TO WRITE INQUIRY QUESTION AND DRAW RAY DIAGRAMS FOR EXPERIMENTS USING MIRRORS?

Syllabus DOT POINT:

3.4a. Conduct a practical investigation to analyse the formation of images in mirrors and lenses via reflection and refraction using the ray model of light (ACSPH075)  

EXPERIMENT (A) Physics Practical Investigation: (A) Wave Depth Studies Reflection and formation of images in plane, convex and concave mirrors. 

AIM: To analyse the formation of reflected images in mirrors.

INQUIRY QUESTION: Link inquiry question to the aim of the experiment and write a hypothesis in the form of a question as shown in the examples below.

  • What are the properties of reflected images in convex, concave and plane mirrors and how are these images formed? (corrected)
  • How are the reflected images in convex, concave and plane mirrors formed using ray diagrams what are the properties of these mages?

What are the characteristics or properties of the reflected image? It is helpful to use SLOT – where:

S – represents the size of the image (same size, magnified or diminished (smaller) compared to the object.

L – represents the location of the image (how far is it from the mirror).

O- represents the orientation of the image (upright or inverted)

T- represents the type of the image (real  or virtual). Real images refers to images formed on the same size as the object and can be captured on a screen. Virtual images are formed on the opposite side of the object.

(i) size of the image compared to the actual object (same size or magnified (larger) or diminished (smaller)

(ii) upright

(iii) laterally inverted (left-right reversed)

(iv)real (means the image is formed on the same size of the mirror as the object and can be observed by placing a screen

or virtual  (means the image is formed on the opposite side of the mirror as the object and like see your image behind the mirror).

 

HOW TO DRAW RAY DIAGRAMS CORRECTLY IN A SCIENTIFIC INVESTIGATION?

A – Experiment Using Mirrors  – Drawing Ray diagrams and description of image

1.1 Plane mirror

Ray diagrams -Poorly drawn Ray diagrams – correctly drawn Description of image

Characteristics or properties of the image)

Incorrect ray diagram for plane mirror

Common Mistakes:

  • No arrow (direction) on the reflected ray  
  • Normal drawn but (not labelled)
  • Incorrect labels for angle i and angle r

Correct ray diagram for plane mirror

Comments:

  • Arrow (direction) indicated on reflected ray
  • Normal drawn and labelled
  • Correct label for angle i and angle r.
Image is:

  • Virtual
  • Upright
  • Laterally inverted (left-right reversed)
  • Same distance behind the mirror as the object is in front of the mirror.
  • same size as the object.

 

1.2 Concave mirrors  

 

Ray diagrams -Poorly drawn Ray diagrams – correctly drawn Description of image

Characteristics or properties of the image)

Common Mistakes:

  • Using dotted lines to draw reflected rays.
  • No arrows (direction) on reflected rays
  • Focal point not indicated.
  • Inaccurate drawings of reflected rays leading to inaccurate location of  focal point.
Comments:

  • Arrow (direction) indicated on reflected ray.
  • Correct label for virtual focal point, y.
  • Accurate drawings of reflected rays. Leading to accurate location of focal point.
(i) If the object is placed further than the focal point, the image is:

  • real   
  • magnified if it is more than twice the focal length OR  smaller if between focal length and less than twice the focal length.
  • laterally inverted(left-right reversed)
  • inverted

(ii) If the object is placed closer than the focal  length, the image

  • virtual  
  • Magnified (larger than the original object).  
  • laterally inverted(left-right reversed)
  • inverted

(iii) If the object is placed at the focal  length,

  • virtual  
  • Magnified (larger than the original object).  
  • laterally inverted(left-right reversed)
  • inverted

 

1.3 Convex mirrors

Ray diagrams -Poorly drawn Ray diagrams – correctly drawn Description of image

Characteristics or properties of the image)

Common Mistakes

  • Using solid lines to extrapolate reflected rays behind the mirror.
  • No arrows (direction) on reflected rays
  • Focal point not indicated.

Comments:

  • Using dotted lines to extrapolate                 reflected rays behind the mirror.
  • Correct label for virtual focal point, y.
  • Accurate drawings of reflected rays. Leading to accurate location of focal point.
Image is:

  • Virtual
  • Upright
  • Laterally inverted (left-right reversed)
  • Diminished (smaller than  the object).