Advertisements
Advertisements
Question
Under what conditions permanent electromagnet is obtained if a current carrying solenoid is used? Support your answer with the help of a labelled circuit diagram.
Advertisements
Solution
The following conditions are required to obtain permanent electromagnet when a current-carrying solenoid is used :
- Rod inside the solenoid should be made of a magnetic material like steel which should retain magnetic properties for a long time after magnetization.
- The current through the solenoid should be direct current.
- The number of turns in the solenoid should be large and closely packed so that a strong uniform magnetic field inside it is produced.
APPEARS IN
RELATED QUESTIONS
The adjacent diagram shows a small magnet placed near a solenoid AB. Current is switched on in the solenoid by pressing the key K.
- State the polarity at the ends A and B.
- Will the magnet be attracted or repelled? Give a reason for your answer.
The following diagram shows a spiral coil wound on a hollow carboard tube AB. A magnetic compass is placed close to it. Current is switched on by closing the key.
- What will be the polarity at the ends A and B?
- How will the compass needle be affected? Give reason.
State two ways by which the magnetic field due to a current carrying solenoid can be made stronger.
How is the magnetic field due to a solenoid carrying current affected if a soft iron bar is introduced inside the solenoid?
A current carrying solenoid behaves like a ______.
A current carrying solenoid when freely suspended, it always rests in ______ direction.
- What name is given to a cylindrical coil of diameter less than its length?
- If a piece of soft iron is placed inside the coil mentioned in part (a) and current is passed in the coil from a battery, what name is then given to the device so obtained?
- Give one use of the device mentioned in part (b).
What is a solenoid?
The diagram shows a current-carrying coil passing through a cardboard sheet. Draw three magnetic lines of force on the board.
State two factors on which magnitude of magnetic field at the centre depends.
The adjacent diagram shows a small magnet placed near a solenoid. State whether the magnet is attracted or repelled, as the switch is pressed. Give a reason.
The factors on which one magnetic field strength is produced by current-carrying solenoids depends are
What does the divergence of magnetic field lines near the ends of a current carrying straight solenoid indicate?
The diagram below shows an insulated copper wire wound around a hollow cardboard cylindrical tube. Answer the questions that follow:
- What are the magnetic poles at A and B when the key K is closed?
- State two ways to increase the strength of the magnetic field in this coil without changing the coil.
- If we place a soft iron bar at the centre of the hollow cardboard and replace the DC source with an AC source then will it attract small iron pins toward itself when the current is flowing through the coil?
A circuit contains a battery, a variable resistor and a solenoid. The figure below shows the magnetic field pattern produced by the current in the solenoid.
- State how the magnetic field pattern indicates regions where the magnetic field is stronger.
- What happens to the magnetic field when the current in the circuit is reversed?
Ansari Sir was demonstrating an experiment in his class with the setup as shown in the figure below.
A magnet is attached to a spring. The magnet can go in and out of the stationary coil. He lifted the Magnet and released it to make it oscillate through the coil.
Based on your understanding of the phenomenon, answer the following question.
Is there any difference in the observations in the galvanometer when the Magnet swings in and then out of the stationary coil? Justify your answer.
When does a solenoid behave as a magnet? Draw the pattern of the magnetic field produced inside it showing the directions of the magnetic field lines.
Differentiate between a circular coil and a solenoid.
Draw a neat diagram of a solenoid and name its various components.
Current is flowing through a coil as shown in the figure. Which one of the given figures will correctly depict the magnetic polarity and the direction of the lines of force along the axis of the coil?
