Tag: electromagnetic forces

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

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

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Without the flexibility strip, the striker will not come back to original position when the electrical circuit breaks.

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

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

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When switch is pressed, circuit completes and ringing begins. Hence, electrical energy is converted to sound energy. As switch is released, no current flows and no energy is consumed,

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

Exposed Electric doorbell can be damaged by 

  1. Mechanical damage

  2. High Electric currents

  3. Humidity

  4. All of the above

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Mechanical Damage to metal gong or striker may hinder working of the bell.

High electric currents may cause heating and burning of electrical circuit.
Humidity may cause short circuit between two unconnected wires, causing high electric currents and damage.

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

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

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Striker repeatedly hits the metal gong when doorbell is ringing. 

This can be observed in regular bells used at homes.

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

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

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The working of an electric magnet is based on the magnetic effect of current. When the key is pressed the circuit gets completed and current passes through it causing the electromagnet to get magnetized which in turn attracts the armature. This movement of the armature causes the hammer to strike the gong. However when the armature moves towards the gong the connection between the spring strip and adjusting screw is lost which breaks the circuit and the current flow is stopped thus demagnetizing the electromagnet. This causes the armature to return to its original position and it is thus pulled back due to the spring effect of the spring strip. This process is called a make and break circuit.

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 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

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The working of an electric magnet is based on the magnetic effect of current. When the key is pressed the circuit gets completed and current passes through it causing the electromagnet to get magnetized which in turn attracts the armature. This movement of the armature causes the hammer to strike the gong. However when the armature moves towards the gong the connection between the spring strip and adjusting screw is lost which breaks the circuit and the current flow is stopped thus demagnetizing the electromagnet. This causes the armature to return to its original position and it is thus pulled back due to the spring effect of the spring strip. This process is called a make and break circuit.

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

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

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The working of an electric magnet is based on the magnetic effect of current. When the key is pressed the circuit gets completed and current passes through it causing the electromagnet to get magnetized which in turn attracts the armature. This movement of the armature causes the hammer to strike the gong.

Multiple choice physics electromagnetic forces magnetic field due to a circular current carrying conductor magnetic field produced in a circular loop oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

The strength and direction of the magnetic field depends on ..........

  1. Magnitude of electric current

  2. Direction of electric current

  3. Both A and B

  4. None of the above

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In his experiment Oersted observed that the deflection of the needle compass changed according to the direction of the current and also as the current in the wire increased, the deflection of the needle increased. Thus he inferred that the strength and direction of the magnetic field depends on the magnitude and direction of current.

Multiple choice physics electromagnetic forces magnetic field due to a circular current carrying conductor magnetic field produced in a circular loop oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

Which of the following effects of current does not depend on the direction of current?

  1. Lighting and chemical effects

  2. Heating and lighting effects

  3. Heating and magnetic effects

  4. Magnetic and chemical effects

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Heating effect and lighting effect does not depend on the direction of current.

Multiple choice physics electromagnetic forces magnetic field due to a circular current carrying conductor magnetic field produced in a circular loop oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

What inferences were drawn from Oersteds experiment?

  1. A current or a moving charge produces magnetic field around it

  2. Presence of magnetic field can be detected using a compass needle

  3. The strength and direction of the magnetic field depends on the magnitude and direction of the current

  4. All of the above

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Oersted conducted an experiment to study the magnetic effect of electric current. In this experiment he observed the deflections of a compass needle placed in close proximity of an electric wire carrying current. He observed that in the absence of current the needle came to rest in Earths North-south direction under the influence of Earths magnetic field. However, when the needle was kept in close proximity of an electric wire carrying current it showed deflections in the east and west direction depending on the direction of current. Thus, indicating that the strength and direction of the magnetic field depends on the magnitude and direction of the current.