Course Description

Overview

This course is targeted at Singapore Cambridge GCE O level students, but is also relevant to IGCSE students and Singapore's Integrated program students.

It's said that Albert Einstein first became interested in science when his father gave him a compass. The young Einstein was fascinated by how it kept pointing in the same direction. This would be one of the first incidents on his road to becoming one of the greatest physicists of the 20th century. In truth, the workings of a compass are fairly straightforward. This course hopes to unpack the principles of magnetism that underlie its operation, as well as the workings of other similarly mystifying physical processes.

Course Content

You will learn:

  • How to visualise and draw magnetic fields
  • How to make one magnet become two magnets
  • How to create magnets out of non-magnets
  • How to create non-magnets out of magnets
  • Lots of other cool stuff!

A link to the full O level Physics syllabus can be found here

Course Prerequisites

You will need to know:

  • How to watch videos on your computer

Math Arena

The instructor is from Math Arena.The instructor is absolutely passionate about teaching and you'll find the lessons engaging and ultimately rewarding.

Course curriculum

  • 1

    Introduction

    • Subject Content Requirements
  • 2

    Basic magnet properties

    • Q1 The magnet is strongest near the

    • Q2 Which of the following observations confirms that an object is a magnet?

    • Q3 Two physically identical metal bars X and Y are positioned in the 2 diagrams shown below. If there is a strong attraction in figure 1 and a very weak attraction in figure 2, what are the possible materials for X and Y?
  • 3

    Induced magnetic poles

    • Q4 Two long iron pins are placed at the ends of a bar magnet as shown. Which of the following diagrams, A, B, C, D shows the situation when a shorter magnet is used?

    • Q5 The figure shows a magnet being used to attract a steel needle. The south pole of the magnet is close to the centre Y of the needle. What are the poles induced in the needle at X, Y and Z?

    • Q5 explanation

    • Q6 The figure below shows a strong magnet holding a chain of five small iron rings. If a weak magnet, X is brought close to the end of the last ring, the ring will

    • Q7 Which of the following is an example of induced magnetism?
  • 4

    Attaching and detaching magnetic objects

    • Q8 A bar magnet is broken as shown below. What are the polarities at X and Y?

    • Q9 Two magnets P and Q attract four soft iron bars, F, G, H and I at their poles as shown below. What will happen to the iron bars when the two magnets move towards each other and attract each other?

    • Q10 A light steel bar and a light iron bar are attached to a magnet as shown. What will possibly happen when the magnet is removed?

    • Q11 A steel bar is brought close to a magnet and an iron bar at different regions (1,2,3 and 4). Which of the following regions will the steel bar be attracted to?

    • Q11 explanation
  • 5

    Compass behaviour

    • Q12 When a bar magnet is being suspended freely,

    • Q13 A metal bar PQ hangs from a thin thread and always comes to rest with end P pointing north. Another bar XY of the same metal settles in no definite direction. What happens if the two bars are brought near one another?

    • Q14 Why does a compass always points to the north?

    • Q15 When one end of a magnet is placed near a compass, the pointer (N-pole) of the compass turns and points at the magnet because

    • Q16 A magnet is suspended freely at the North Pole of the Earth. Which of the following shows the correct direction of the magnet?
  • 6

    The magnetic field - field line direction

    • Q17 A plotting compass is placed beside a bar magnet as shown below. Which of the drawings shows the correct direction of the compass needle?

    • Q18 Four plotting compasses are placed near a bar magnet. You may ignore any effects of the Earth’s magnetic field. One compass appears like this [image]. What is a possible position for this compass?

    • Q19 A compass is placed near a copper bar as shown in the diagram. In which direction will the compass needle point?

    • Q20 Which of the following diagrams shows the correct magnetic field pattern between the poles of two bar magnet?

    • Q21 Which diagram below indicates the correct magnetic field pattern between the poles of two bar magnet?

    • Q22 A compass is placed between two magnets of equal magnetic strength as shown in the diagram. In which direction will the compass needle point?

    • Q23 A compass is placed between two magnets as shown in the diagram. Magnet X is stronger than magnet Y. In which direction will the compass needle point?

    • Q24 Fig 1 below shows the magnetic field near a bar magnet and an object XY. In Fig 2, XY has been turned around. What could XY be?

    • Q25 The diagram below shows the magnetic field of 2 magnets placed close together. Three plotting compasses are placed at the locations shown. Which is the set of compasses showing the correct direction of the needles?

    • Q26 The diagram shows the magnetic field of 2 magnets placed close together with 3 plotting compasses placed at the locations shown. Which is the set of compasses showing the correct direction of the needles?

    • Q27 A bar magnet is placed in a uniform magnetic field as shown. The magnet will

    • Q28 The diagram shows a bar magnet being placed in a magnetic field. What will happen to the bar magnet?

    • Q29 The diagram at the below represents a bar magnet. The direction of the magnetic field at point P is toward point

    • Q30 In the diagram above, what is the direction of the magnetic field at point P?
  • 7

    The magnetic field - magnetic field strength

    • Q31 The diagram below represents magnetic lines of force within a region of space. The magnetic field is strongest at point __?

    • Q32 In which diagram below is the magnetic field strength at point P greatest?

    • Q33 In the diagram below, a steel paper clip is attached to a string, which is attached to a table. The clip remains suspended beneath a magnet. As the magnet is lifted, the paper clip begins to fall as a result of
  • 8

    The magnetic field - magnetic shielding

    • Q34 A metal ring screens a piece of equipment from a magnetic field. Which metal should be used for the ring, and why?

    • Q34 explanation

    • Q35 Diagram 1 shows a compass needle pointing to the earth north when there are no other magnets around it. The compass is then placed at a point Z near to the magnet surround by a soft iron ring. Which diagram shows the orientation of the compass needle?
  • 9

    Magnetisation - Stroking method

    • Q36 Which of the following are possible results when a steel bar is being magnetised by stroking?

    • Q37 Which of the following is/are possible result(s) when a steel bar is being magnetised by double stroking method?

    • Q38 Which of the following are possible sets of polarity when magnetising a steel bar by stroking method?
  • 10

    The solenoid

    • Q39 What is the main reason for using a solenoid instead of a straight wire to produce magnetic field?

    • Q40 Which coil produces the greatest magnetic field strength for a given flow of current?

    • Q41 Which coil produces the strongest electromagnet for a given flow of current?

    • Q42 Which is the strongest electromagnet?

    • Q43 In which diagram(s) is/are the correct poles for the electromagnet indicated?

    • Q44 The diagram shows a small magnet hanging on a thread near the end of a solenoid carrying a steady current I. What happens to the magnet as the iron core is inserted into the solenoid?

    • Q45 A current-carrying wire is coiled around an iron horseshoe as shown. What are the polarities of X and Y?

    • Q46 The diagram below shows the circuit of an electric bell. What happens when the bell button is switched on and switched off?
  • 11

    Demagnetisation

    • Q47 Which of the following methods is the most effective when demagnetizing a magnet?

    • Q48 Which of the following is the correct sequence to effectively demagnetise a steel bar using electrical method?
  • 12

    Structured Questions

    • SQ1 Two bar magnets in parallel

    • SQ2 Perpendicular magnets

    • SQ3 Electromagnetic lock

    • SQ4 Steel and iron bars attracted to permanent magnet

    • SQ5 Permanent magnet lifting rods off a bench

    • SQ6 Compass needle placed near bar magnet

    • SQ7 (part 1) Magnetic field lines true or false statements

    • SQ7 (part 2) Magnetic field lines field produced by a current-carrying conductor