Magnetism and Electromagnetism
What is the shape of the magnetic field lines around a long, straight, current-carrying wire?
Straight lines parallel to the wire
Concentric circles around the wire
Straight lines radiating outward from the wire
Spirals along the wire
A wire carries a current of 2 A along the positive z-axis. A magnetic field of 0.3 T is directed along the positive x-axis. What is the direction of the magnetic force on the wire?
Positive y-axis
Negative y-axis
Positive x-axis
Negative x-axis
A flexible wire carrying a current is placed in a uniform magnetic field. If the wire is initially straight, what will happen to the wire due to the magnetic force?
The wire will remain straight
The wire will curve to form a circle
The wire will break
The wire will oscillate
A long, straight wire carries a current of 4 A. What is the magnitude of the magnetic field at a distance of 2 cm from the wire? (Assume T⋅m/A)
4 × 10⁻⁵ T
2 × 10⁻⁵ T
4 × 10⁻⁷ T
2 × 10⁻⁷ T
A circular loop of wire carries a current in a clockwise direction. According to Right-Hand Rule #1 (RHR1), what is the direction of the magnetic field at the center of the loop?
Into the page
Out of the page
Left
Right
Two identical current loops are placed coaxially a short distance apart. One loop carries a clockwise current, and the other carries a counter-clockwise current. What is the direction of the net magnetic field midway between the loops on the axis?
Towards the clockwise loop
Towards the counter-clockwise loop
Zero
Impossible to determine
Under what conditions is the magnetic force on a current-carrying wire in a magnetic field equal to zero?
When the wire is parallel to the magnetic field
When the wire is perpendicular to the magnetic field
When the current is maximum
When the magnetic field is maximum

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A wire carries a current from left to right and is placed in a magnetic field pointing into the page. According to Right-Hand Rule #2 (RHR2), what is the direction of the force on the wire?
Upward
Downward
Into the page
Out of the page
Two long, straight wires carry currents and in the same direction. They are separated by a distance d. At a point midway between the wires, the net magnetic field is zero. What can be concluded about the relationship between and ?
A straight wire of length 0.2 m carries a current of 3 A in a uniform magnetic field of 0.5 T. The angle between the wire and the magnetic field is 90 degrees. What is the magnitude of the magnetic force on the wire?
0.3 N
0.6 N
0 N
1.2 N