Magnetic Field Due to an Electric Current Mcq
According to Ampere’s law, the magnetic field produced by an electric current is:
a) Proportional to the voltage
b) Inversely proportional to the current
c) Proportional to the current
d) Inversely proportional to the resistance
Answer: c) Proportional to the current
The direction of the magnetic field around a straight current-carrying wire is:
a) Away from the wire
b) Towards the wire
c) Clockwise around the wire
d) Counterclockwise around the wire
Answer: d) Counterclockwise around the wire
The strength of the magnetic field around a current- carrying wire depends on:
a) The length of the wire
b) The resistance of the wire
c) The current in the wire
d) The voltage across the wire
Answer: c) The current in the wire
The SI unit of magnetic field strength is:
a) Ampere
b) Ohm
c) Volt
d) Tesla
Answer: d) Tesla
The magnetic field around a current-carrying wire follows which law?
a) Ohm’s law
b) Faraday’s law
c) Ampere’s law
d) Coulomb’s law
Answer: c) Ampere’s law
The magnetic field lines around a current-carrying wire form:
a) Circles
b) Straight lines
c) Spirals
d) Hyperbolas
Answer: a) Circles
The strength of the magnetic field around a current-carrying wire:
a) Decreases with increasing distance from the wire
b) Increases with increasing distance from the wire
c) Remains constant at all distances from the wire
d) Depends on the resistance of the wire
Answer: a) Decreases with increasing distance from the wire
The right-hand rule for magnetic fields states that if you point your thumb in the direction of the current, your fingers curl in the direction of the:
a) Electric field
b) Magnetic field
c) Voltage
d) Current density
Answer: b) Magnetic field
The magnetic field inside a current-carrying solenoid is:
a) Zero
b) Parallel to the axis of the solenoid
c) Perpendicular to the axis of the solenoid
d) Varies randomly inside the solenoid
Answer: b) Parallel to the axis of the solenoid
The magnetic field inside a current-carrying straight wire is:
a) Zero
b) Concentrated at the center of the wire
c) Uniform along the length of the wire
d) Varies randomly inside the wire
Answer: c) Uniform along the length of the wire
The magnetic field inside a current-carrying loop of wire is:
a) Zero
b) Concentrated at the center of the loop
c) Uniform along the perimeter of the loop
d) Varies randomly inside the loop
Answer: b) Concentrated at the center of the loop
The strength of the magnetic field produced by a current-carrying wire is:
a) Inversely proportional to the length of the wire
b) Directly proportional to the square of the current
c) Inversely proportional to the resistance of the wire
d) Directly proportional to the distance from the wire
Answer: d) Directly proportional to the distance from the wire
The magnetic field produced by a current-carrying wire decreases with distance according to:
a) Inverse square law
b) Direct square law
c) Inverse cube law
d) Direct cube law
Answer: a) Inverse square law
The strength of the magnetic field produced by a current-carrying wire is:
a) Independent of the material of the wire
b) Dependent on the temperature of the wire
c) Dependent on the diameter of the wire
d) Independent of the current in the wire
Answer: a) Independent of the material of the wire
The magnetic field produced by a current-carrying wire can be increased by:
a) Increasing the length of the wire
b) Increasing the resistance of the wire
c) Increasing the voltage across the wire
d) Increasing the number of turns in the wire
Answer: d) Increasing the number of turns in the wire
The magnetic field produced by a current-carrying wire is strongest:
a) Inside the wire
b) Outside the wire
c) At the ends of the wire
d) Along the sides of the wire
Answer: b) Outside the wire
The magnetic field produced by a current-carrying wire is weaker when the wire is:
a) Straight
b) Coiled
c) Bent into a loop
d) None of the above
Answer: a) Straight
The magnetic field produced by a current-carrying wire is zero when the wire forms a:
a) Straight line
b) Circular loop
c) Helix
d) Coil
Answer: a) Straight line
The strength of the magnetic field produced by a current -carrying wire is halved when the distance from the wire is:
a) Doubled
b) Tripled
c) Quadrupled
d) Halved
Answer: a) Doubled
The magnetic field produced by a current-carrying wire is strongest when the wire is:
a) Thick
b) Thin
c) Long
d) Short
Answer: a) Thick
The direction of the magnetic field inside a current-carrying coil is:
a) Clockwise
b) Counterclockwise
c) Towards the center of the coil
d) Away from the center of the coil
Answer: c) Towards the center of the coil
The strength of the magnetic field produced by a current-carrying coil is increased by:
a) Increasing the diameter of the coil
b) Increasing the number of turns in the coil
c) Decreasing the current in the coil
d) Decreasing the resistance of the coil
Answer: b) Increasing the number of turns in the coil
The magnetic field produced by a current-carrying coil is concentrated in:
a) The core of the coil
b) The wire of the coil
c) The surrounding space outside the coil
d) Both the core and the surrounding space
Answer: d) Both the core and the surrounding space