Electric Bell - Working Principle and Components
Questions about the working mechanism, components, circuit behavior, and related concepts of electric bells/doorbells
Questions
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.
- $3$
- $4$
- $5$
- $Can't\ be\ determined$
Name one device that uses an electromagnet.
- Electric bell
- Barometer
- Lactometer
- All the above
What material is used for making the armature of an electric bell ? Give a reason for using this material.
- Soft Iron
- Carbon
- Glass
- Silicon
Working of electric bells is an example of
- Mechanical effect of electric current
- Heating effect of electric current
- Magnetic effect of electric current
- None of these
Electric door bell employs
- Permanent Magnet
- Electromagnet
- Thermistor
- Electric bulb
When the switch of an electric bell is pushed.
- Flow of the current stops through the electromagnet in the bell
- Current starts to flow through the electromagnet
- Voltage decreases in the current flowing through the electromagnet
- None of the above
Which of the following is not a component of electric bell?
- Gong
- Ferromagnetic strip
- Low magnetic field permanent magnet to attract ferromagnetic strip
- None of the above
Which of the following is a characteristic of a buzzer?
- It has different mechanism from electric bell.
- It has higher frequency of collision of gong and hammer
- It uses only AC power supply
- None of the above
Which power supply can be used in electric bell
- $AC$
- $DC$
- Can't be predicted
- Both A and B
When the switch of an electric bell is pushed
- Flow of the current stops through the electromagnet in the bell
- Current starts to flow through the electromagnet
- Voltage decreases in the current flowing through the electromagnet
- Circuit is closed in the electric bell
When the switch of an electric bell is on then electric current in it :
- Flows and stops in succession
- Flows continuously
- First flows in one direction and after sometime in other direction
- Flows in beginning and then stops forever
Why doorbell rings repeatedly when switch is pressed
- Because of nature of current
- Because electrical switch is built in such a manner
- Because of make and break arrangement
- Because of slight humidity in the circuit
What will happen if the strip in a doorbell loses its flexibility?
- Striker may break if current is large.
- After hitting the metal gong, it never returns to original position and only a single sound is produced.
- System of doorbell breaks
- Both A and B
What is the use of flexibility strip in a doorbell?
- It brings back striker to its original position
- It supports the motion of the striker
- It completes the electric circuit flexibly
- Its a safety precaution
Electric doorbell
- Always consume power
- Consume power only when switch is pressed
- Do not consume power practically and needs only starting power
- cant say
Exposed Electric doorbell can be damaged by
- Mechanical damage
- High Electric currents
- Humidity
- All of the above
During a doorbell ringing
- Current always flows in the circuit
- Electromagnet is always present
- Striker is always in contact with metal gong
- Striker always repeatedly hits metal gong
Armature is pulled towards the spring when it strikes the gong because
- The electromagnet gets demagnetized
- The current flow breaks
- Spring effect
- All of the above
Which process is applied on a circuit for the working of an electric bell?
- Magnetization
- Make and break
- Both A and B
- None of the above
The hammer hits the gong because
- It has electric charge
- It displays the spring effect
- It is attracted towards the electro-magnet
- All of the above