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Using electromagets

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Lesson outcome

Waxaan sharxi karaa sida elektromagnetic-yada loogu isticmaalo wiishashka, qufulka, gambaleelka, iyo matoorada.

Introduction

In this lesson: I can describe how electromagnets are used in cranes, locks, bells and motors. An electromagnetic door lock uses an electromagnet to pull a magnetic bolt to unlock a door. An electric bell often contains an electromagnet that attracts and moves the striker, making it hit the bell.

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An electromagnetic door lock uses an electromagnet to pull a magnetic bolt to unlock a door. An electric bell often contains an electromagnet that attracts and moves the striker, making it hit the bell. As an electromagnet moves the striker in an electric bell, it breaks its own circuit to let the striker spring back. A motor contains a spinning coil of wire that is an electromagnet. When there is a current in the spinning coil of wire in a motor, other magnets around it will push it round.

Worksheet

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Quizzes

  1. 1. An object that always behaves as a magnet is called a __________ magnet.

    • Correct answer:permanent
    • persistent
    • continuous
    • constant
    • steady

  2. 2. Which of the following objects would be attracted to an electromagnet?

    • Correct answer:a nickel coin
    • a copper nail
    • Correct answer:a steel spanner
    • Correct answer:an iron pin
    • a piece of aluminium foil

  3. 3. Which of the following statements explain why soft iron is usually used for the core of an electromagnet?

    • Soft iron is a poor conductor of electricity.
    • Soft iron is a good conductor of electricity.
    • Correct answer:Soft iron is a magnetic material.
    • Correct answer:Soft iron becomes magnetised easily.
    • Correct answer:Soft iron loses its magnetism easily.

  4. 4. Which of the following is a definition of a complete circuit?

    • A circuit that contains a battery.
    • Correct answer:A circuit that is a closed loop.
    • A circuit that includes at least one bulb or resistor.
    • A circuit made up of straight sections of wire.

  5. 5. A pupil has a coil of wire coated in yellow plastic, as shown. They attach metal clips to the ends of the coil and connect them to a suitable battery. Why is there no magnetic field around the coil?

    • Plastic blocks magnetic fields.
    • Plastic is not a magnetic material.
    • Correct answer:Plastic is an electrical insulator
    • The magnetic fields around the left and right sides of the wire cancel out.

  6. 6. A pupil experiments with a bar magnet and an electromagnet. Which of the following statements are correct?

    • The bar magnet and electromagnet can repel but cannot attract each other.
    • The bar magnet and electromagnet can attract but cannot repel each other.
    • Correct answer:The bar magnet and electromagnet can attract and repel each other.
    • The bar magnet and electromagnet cannot attract or repel each other.

  1. 1. An electromagnet that loses its magnetism when current stops flowing can also be called a __________ magnet.

    • Correct answer:temporary
    • part–time
    • freelance
    • short–term

  2. 2. A scrapyard uses an electromagnet to move objects made of a magnetic material such as steel. Which of the following describe an advantage of using an electromagnet compared with a permanent magnet?

    • Electromagnets attract all types of metal.
    • Correct answer:An electromagnet can be switched off.
    • An electromagnet has one pole instead of two.
    • An electromagnet has two of the same type of pole.

  3. 3. Which of the following is the purpose of the springs attached to the bolt of the electromagnetic door lock shown?

    • They attract the bolt when a current flows in them.
    • They are attracted to the electromagnet when a current flows in them.
    • Correct answer:They pull the bolt into the door when the electromagnet is switched off.
    • They pull the bolt out of the door when the electromagnet is switched off.

  4. 4. The diagram shows an electric door lock. Which of the following statements are correct?

    • The door is locked.
    • Correct answer:The door is unlocked.
    • Correct answer:The electromagnet is switched on.
    • The electromagnet is switched off.

  5. 5. The diagram shows an electric bell. Which of the following happen as the switch is pressed?

    • The electromagnet stops being magnetised.
    • Correct answer:The electromagnet becomes magnetised.
    • Correct answer:The clapper moves up with the iron armature.
    • The clapper moves down with the iron armature.

  6. 6. Which of the following statements describes the function of an electric motor?

    • Correct answer:It uses a magnetic field and a current to produce a force.
    • It uses a force and a current to produce a magnetic field.
    • It uses a magnetic field and a force to produce a current.

What pupils see

The same lesson as a pupil sees it. You can set any section as work on its own.

  • IntroductionPrepare
  • Starter quizActivate · 6 questions
  • Lesson videoLearn
  • Exit quizCheck · 6 questions
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