Tag: electromagnetic forces

Questions Related to electromagnetic forces

Thermistor material is pressed ________

physics electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

  1. under zero pressure

  2. under low pressure

  3. under high pressure

  4. under low volume

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Correct Option: C
Explanation:

A thermistor material is usually pressed under high pressure to form a flat cylindrical shape. Disks and washers are placed in series or in parallel to increase the power dissipation.

Thermistors have ________

physics electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

  1. positive temperature coefficient

  2. negative temperature coefficient

  3. zero temperature coefficien

  4. infinite temperature coefficient

Show answer
Correct Option: B
Explanation:

Thermistor generally has a negative temperature coefficient of resistance. With increase in temperature, resistance of a thermistor decreases.

Thermistor follows which law for small variations ________

physics electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

  1. Charles law

  2. KVL

  3. KCL

  4. Ohms law

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Correct Option: D
Explanation:

For small changes in the values of current, voltage across a thermistor increases. It attains a peak value. Then the voltage across the thermistor decreases. As a result Ohms law is followed at small variations of current.

Who discovered the relationship between electricity and magnetism

physics electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

  1. Faraday

  2. Newton

  3. Maxwell

  4. Oersted

Show answer
Correct Option: D
Explanation:

Answer is D.

Electromagnetism is the study of the electromagnetic force which is a type of physical interaction that occurs between electrically charged particles. 
Hans Christian Oersted discovered the relationship between electricity and magnetism in 1820.

Who discovered the relationship between electricity and magnetism?

physics electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

  1. Faraday

  2. Newton

  3. Maxwell

  4. Oersted

Show answer
Correct Option: D
Explanation:

Answer is D.

Electromagnetism is the study of the electromagnetic force which is a type of physical interaction that occurs between electrically charged particles. 
Hans Christian Oersted discovered the relationship between electricity and magnetism in 1820.

With _____ in current in a wire near to magnetic needle, _____the vibration in the needle. Fill in the blank.

physics electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

  1. increase, decreases

  2. increase, increases

  3. decrease, increases

  4. Non of above 

Show answer
Correct Option: B
Explanation:

More is the current in the wire near to the magnetic field, more is the strength of magnetic field generated around the wire and thus more is the vibration in the needle.

What did Orested do in the experiment ?

physics electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

  1. Placed a compass near an electromagnet and observed its deflection

  2. Placed a compass near a magnet and observed the deflection of compass needle

  3. Placed a compass near a current carrying wire and observed the deflection of compass needle

  4. Placed a compass near an electrolyte and observed the deflection of compass needle

Show answer
Correct Option: C
Explanation:

Hans Christian Oersted. Hans Christian Oersted began a new scientific epoch when he discovered that electricity and magnetism are linked. He showed by experiment that an electric current flowing through a wire could move a nearby magnet.Oersted's experiment that when an electric current is passed through a conducting wire, a magnetic field is produced around it. The presence of magnetic field at a point around a current carrying wire can be detected with the help of a compass needle

The amount of deflection of the magnetic needle in a galvanoscope depends on:

physics electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

  1. The amount of current passing through the insulated copper wire that is wound over it

  2. Magnetic strength of the magnetic needle

  3. Number of turns of the coil

  4. All the above

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Correct Option: D
Explanation:

The deflection in galvanometer is the defined by 

$\tau=NBIA$
The N is number of turns of coils.
B is magnetic strenght of magnetic needles 
I is The amount of current passing through the insulated copper wire that is wound over it
A is area of coil contact with magnetic field.

What did Oersted observe while performing the experiment ?

physics electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

  1. The compass needle placed near an electromagnet deflected

  2. The compass needle kept near an electrolyte deflected

  3. The compass needle kept near a wire carrying electric current deflected when the current was switched ON and OFF.

  4. None of the above

Show answer
Correct Option: C
Explanation:

Oersted observed while performing the experiment when he passed a current through a wire which caused a nearby magnetic compass needle to move.When current switched off then needle comes to their original position

What did Orested discover from his experiment ?

physics electromagnetic forces oersted experiment oersted's experiment magnetic field due to a straight current carrying conductor

  1. Heating effect of electric current

  2. Magnetic effect of electric current

  3. Chemical effect of electric current

  4. Physical effect of electric current

Show answer
Correct Option: B
Explanation:

In the experiment of Oersted's he passed electric current through a wire,which caused a nearby magnetic field so that compass needle move.That shows that magnetic effect of eclectic current.