An isosceles triangular current-carrying loop is kept perpendicularly in a uniform magnetic field as shown in the figure. The force on the loop due to magnetic field is:
1
2
3
4
Official Solution
Correct Option: (3)
In a uniform magnetic field, the net force on any closed current loop is zero. Each segment may experience a magnetic force, but by symmetry and vector addition, the total force cancels out. In this case:
- The loop is symmetric.
- Magnetic forces on opposite sides are equal and opposite in direction.
- Thus, net magnetic force on the loop = 0. \
02
PYQ 2022
medium
physicsID: ap-eapce
A charged particle is moving in a uniform magnetic field and enters a lead layer, losing half of its kinetic energy. The radius of curvature of its path becomes:
1
No change
2
Reduced by times of its initial value
3
Reduced to times of its initial value
4
Reduce to times of its initial value
Official Solution
Correct Option: (3)
The radius of curvature in a magnetic field is given by:
Kinetic energy:
If kinetic energy becomes half:
So, the radius decreases by a factor of .
03
PYQ 2023
medium
physicsID: ap-eapce
The magnetic force is
1
parallel to both and
2
perpendicular to
3
perpendicular to both and
4
parallel to
Official Solution
Correct Option: (3)
The magnetic force on a charged particle moving with velocity in a magnetic field is given by:
Where:
- is the charge of the particle,
- is the velocity vector,
- is the magnetic field vector. This force is always perpendicular to both the velocity and the magnetic field . Thus, the force is perpendicular to both and , which is the correct option.
04
PYQ 2023
medium
physicsID: ap-eapce
A magnetic field of 1 T is acting on a wire carrying a current of 1 A so that the wire is at rest in air. If the mass of the wire is 100 g, then the length of the wire is:
1
1 m
2
0.5 m
3
2 m
4
0.25 m
Official Solution
Correct Option: (1)
The force due to the magnetic field on the wire is: The weight of the wire is: For the wire to be at rest, the magnetic force must balance the weight of the wire: Substitute the values: Solving for : Thus, the length of the wire is approximately 1 m.
05
PYQ 2023
medium
physicsID: ap-eapce
An electron moving along positive x-direction with velocity ms enters a magnetic field of T. The magnitude of the force acting on the electron is:
1
2
3
4
Official Solution
Correct Option: (2)
The force on a charged particle moving in a magnetic field is given by the equation . Using the given values for velocity and magnetic field , we calculate the cross product and find the magnitude of the force acting on the electron as .
