Electric Bell - Working Principle and Components

Questions about the working mechanism, components, circuit behavior, and related concepts of electric bells/doorbells

20 Questions Published

Questions

Question 1 Multiple Choice (Single Answer)

An electric bell has a resistance of $5 \Omega$ and requires a current of $0.25\ A$ to work it. Assuming that the resistance of the bell wire is $1 \Omega$ per $15m$ and that the bell push is $90m$ distance from the bell. How many cells each of emf $1.4V$ and internal resistance $2 \Omega$, will be required to work the circuit.

  1. $3$
  2. $4$
  3. $5$
  4. $Can't\ be\ determined$
Question 2 Multiple Choice (Single Answer)

Name one device that uses an electromagnet.

  1. Electric bell
  2. Barometer
  3. Lactometer
  4. All the above
Question 3 Multiple Choice (Single Answer)

What material is used for making the armature of an electric bell ? Give a reason for using this material.

  1. Soft Iron
  2. Carbon
  3. Glass
  4. Silicon
Question 4 Multiple Choice (Single Answer)

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
Question 5 Multiple Choice (Single Answer)

Electric door bell employs

  1. Permanent Magnet
  2. Electromagnet
  3. Thermistor
  4. Electric bulb
Question 6 Multiple Choice (Single Answer)

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
Question 7 Multiple Choice (Single Answer)

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
Question 8 Multiple Choice (Single Answer)

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
Question 9 Multiple Choice (Single Answer)

Which power supply can be used in electric bell

  1. $AC$
  2. $DC$
  3. Can't be predicted
  4. Both A and B
Question 10 Multiple Choice (Single Answer)

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
Question 11 Multiple Choice (Single Answer)

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
Question 12 Multiple Choice (Single Answer)

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
Question 13 Multiple Choice (Single Answer)

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
Question 14 Multiple Choice (Single Answer)

What is the use of flexibility strip in a doorbell?

  1. It brings back striker to its original position
  2. It supports the motion of the striker
  3. It completes the electric circuit flexibly
  4. Its a safety precaution
Question 15 Multiple Choice (Single Answer)

Electric doorbell

  1. Always consume power
  2. Consume power only when switch is pressed
  3. Do not consume power practically and needs only starting power
  4. cant say
Question 16 Multiple Choice (Single Answer)

Exposed Electric doorbell can be damaged by 

  1. Mechanical damage
  2. High Electric currents
  3. Humidity
  4. All of the above
Question 17 Multiple Choice (Single Answer)

During a doorbell ringing

  1. Current always flows in the circuit
  2. Electromagnet is always present
  3. Striker is always in contact with metal gong
  4. Striker always repeatedly hits metal gong
Question 18 Multiple Choice (Single Answer)

Armature is pulled towards the spring when it strikes the gong because

  1. The electromagnet gets demagnetized
  2. The current flow breaks
  3. Spring effect
  4. All of the above
Question 19 Multiple Choice (Single Answer)

Which process is applied on a circuit for the working of an electric bell?

  1. Magnetization
  2. Make and break
  3. Both A and B
  4. None of the above
Question 20 Multiple Choice (Single Answer)

The hammer hits the gong because

  1. It has electric charge
  2. It displays the spring effect
  3. It is attracted towards the electro-magnet
  4. All of the above