Tag: electromagnetic forces

Quizzes (4) Questions (60)

Questions Related to electromagnetic forces

Multiple choice physics current electricity and magnetism electric bell the magnetic effect of a current electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

Working of electric bells is an example of

  1. Mechanical effect of electric current

  2. Heating effect of electric current

  3. Magnetic effect of electric current

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

An electric bell contains an electromagnet, consisting of coils of insulated wire wound round iron rods. When an electric current flows through the coils, the rods become magnetic and attract a piece of iron attached to a clapper. The clapper hits the bell and makes it ring.

Multiple choice physics current electricity and magnetism electric bell the magnetic effect of a current electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

When the switch of an electric bell is pushed.

  1. Flow of the current stops through the electromagnet in the bell

  2. Current starts to flow through the electromagnet

  3. Voltage decreases in the current flowing through the electromagnet

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the switch of electric bell is pushed,circuit completes and current flows leading an electromagnet to attract armature and ring the bell.

Multiple choice physics current electricity and magnetism electric bell the magnetic effect of a current electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

Which of the following is not a component of electric bell?

  1. Gong

  2. Ferromagnetic strip

  3. Low magnetic field permanent magnet to attract ferromagnetic strip

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Electric bell works on the mechanism of electromagnets i.e, temporary magnets, and no permanent magnet is used.

Temporary magnet allows the ferromagnetic strip to return back to its initial state as switch is released.

Multiple choice physics current electricity and magnetism electric bell the magnetic effect of a current electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

Which of the following is a characteristic of a buzzer?

  1. It has different mechanism from electric bell.

  2. It has higher frequency of collision of gong and hammer

  3. It uses only AC power supply

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In a buzzer, the simplest sort of doorbell, an electromagnet is used to operate a self-interrupting circuit. You can see how this system works in the diagram below. Click and hold the doorbell button to see how the buzzer works. ... This breaks the doorbell circuit, which shuts off the electromagnet.characteristic of a buzzer It has higher frequency of collision of gong and hammer

Multiple choice physics current electricity and magnetism electric bell the magnetic effect of a current electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

Which power supply can be used in electric bell

  1. $AC$
  2. $DC$

  3. Can't be predicted

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Electric bell works on the mechanism of electromagnets and for this any type of power either AC or DC can be used.

Multiple choice physics current electricity and magnetism electric bell the magnetic effect of a current electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

When the switch of an electric bell is pushed

  1. Flow of the current stops through the electromagnet in the bell

  2. Current starts to flow through the electromagnet

  3. Voltage decreases in the current flowing through the electromagnet

  4. Circuit is closed in the electric bell
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
When the switch of an electric bell is pushed, current start to flow through the electromagnet.
When switch is pushed , circuit is closed and current starts flowing through the electromagnet in bell & bell starts ringing.
OPTION : B.
Multiple choice physics current electricity and magnetism electric bell the magnetic effect of a current electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

When the switch of an electric bell is on then electric current in it :

  1. Flows and stops in succession

  2. Flows continuously

  3. First flows in one direction and after sometime in other direction

  4. Flows in beginning and then stops forever
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The bell works on the principle of electromagnetism which says that when an electric current flows through the coil, the rods become magnetic and attract a piece of iron attached to a clapper. And the clapper hits the cap and comes back as the current stops, and hence the bell rings. So the current flows and stops in succession. And in this way the bell rings.

Multiple choice physics current electricity and magnetism electric bell the magnetic effect of a current electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

Why doorbell rings repeatedly when switch is pressed 

  1. Because of nature of current

  2. Because electrical switch is built in such a manner

  3. Because of make and break arrangement

  4. Because of slight humidity in the circuit
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Make and break arrangement causes striker to repeatedly hit the metal gong as long as switch is pressed. When Circuit is complete, electromagnet attracts the striker which hits metal gong. As soon as the striker moves, circuit breaks and electromagnet is inactive. Because of flexibility of striker, it moves back to its original position. As soon as it reaches original position, circuit is complete. This process repeats continuously. 

Multiple choice physics current electricity and magnetism electric bell the magnetic effect of a current electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

What will happen if the strip in a doorbell loses its flexibility?

  1. Striker may break if current is large.

  2. After hitting the metal gong, it never returns to original position and only a single sound is produced.

  3. System of doorbell breaks

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Because of lack of flexibility, striker will resist change of motion more and may break if current is large.

Without flexibility, no rebounding force is present and striker will not return to its original position.