Q1. When an electric current flows through a straight conductor, what is the shape of the magnetic field produced around it?
a) Circular
b) Elliptical
c) Spherical
d) Straight
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Correct Answer: a) Circular
Explanation: When an electric current flows through a straight conductor, it produces a circular magnetic field around the conductor, following the right-hand rule.
Q2. Which rule is used to determine the direction of the magnetic field around a current-carrying conductor?
a) Ampère’s Law
b) Ohm’s Law
c) Fleming’s Left-hand Rule
d) Fleming’s Right-hand Rule
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Correct Answer: d) Fleming’s Right-hand Rule
Explanation: Fleming’s Right-hand Rule is used to determine the direction of the magnetic field around a current-carrying conductor, where the thumb points in the direction of the current and fingers curl in the direction of the magnetic field.
Q3. What is the term for the phenomenon where a magnetic field is produced around a current-carrying conductor?
a) Electromagnetic induction
b) Magnetic induction
c) Faraday’s Law
d) Ampère’s Law
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Correct Answer: b) Magnetic induction
Explanation: Magnetic induction refers to the generation of a magnetic field around a current-carrying conductor, which is a fundamental principle of electromagnetism.
Q4. Which device is used to detect the presence and direction of a small current in a circuit?
a) Voltmeter
b) Ammeter
c) Galvanometer
d) Ohmmeter
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Correct Answer: c) Galvanometer
Explanation: A galvanometer is a sensitive device used to detect the presence and direction of a small current in a circuit, often used as the basis for ammeters and voltmeters.
Q5. What is the SI unit of magnetic field strength?
a) Tesla
b) Ampere
c) Weber
d) Henry
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Correct Answer: a) Tesla
Explanation: The SI unit of magnetic field strength is the Tesla (T), which is defined as one Newton per Ampere per meter (N/A·m).
Q6. What happens to the strength of the magnetic field around a current-carrying conductor when the current is increased?
a) Increases
b) Decreases
c) Remains constant
d) Depends on the material of the conductor
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Correct Answer: a) Increases
Explanation: The strength of the magnetic field around a current-carrying conductor increases with an increase in the current flowing through the conductor, as stated by Ampère’s Law.
Q7. Which of the following materials is commonly used as a core for electromagnets?
a) Copper
b) Aluminium
c) Iron
d) Silver
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Correct Answer: c) Iron
Explanation: Iron is commonly used as a core for electromagnets due to its high magnetic permeability, allowing for stronger magnetic fields to be produced.
Q8. What is the term for the property of a material that allows it to become magnetized when placed in a magnetic field?
a) Permeability
b) Resistivity
c) Conductivity
d) Reluctance
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Correct Answer: a) Permeability
Explanation: Permeability is the property of a material that allows it to become magnetized when placed in a magnetic field, influencing the strength of the magnetic field produced.
Q9. What is the term for the device used to increase or decrease the voltage in an alternating current (AC) circuit?
a) Transformer
b) Rectifier
c) Capacitor
d) Inductor
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Correct Answer: a) Transformer
Explanation: A transformer is a device used to increase or decrease the voltage in an alternating current (AC) circuit by electromagnetic induction, consisting of primary and secondary coils wrapped around a common core.
Q10. Which law states that the magnetic field produced around a current-carrying conductor is directly proportional to the current and inversely proportional to the distance from the conductor?
a) Ampère’s Law
b) Ohm’s Law
c) Faraday’s Law
d) Coulomb’s Law
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Correct Answer: a) Ampère’s Law
Explanation: Ampère’s Law states that the magnetic field produced around a current-carrying conductor is directly proportional to the current flowing through the conductor and inversely proportional to the distance from the conductor.