Concepts Of Physics MCQ Edition [Volume 2]
- Exam
- Concepts Of Physics MCQ Edition [Volume 2]
- Subject
- Physics
- Chapter
- Electric Field and Potential
Concepts Of Physics MCQ Edition [Volume 2] · Physics · Electric Field and Potential
An electric dipole is placed within an electric field produced by a...
An electric dipole is placed within an electric field produced by a point charge.
Options
- AThe net electric force on the dipole could be zero
- BThe net electric force on the dipole must always be zero
- CThe torque on the dipole due to the field must always be zero
- DThe torque on the dipole due to the field could be zero
Correct answer
D. The torque on the dipole due to the field could be zero
Step-by-step solution
The electric field produced by a point charge is non-uniform, as its magnitude varies with distance and its direction is radial.
Since the two charges of the dipole are at different positions, they will experience different electric fields ().
The net force on the dipole is . Thus, the net electric force can never be zero.
The torque on the dipole is given by .
If the dipole is placed such that its dipole moment is parallel or anti-parallel to the electric field (i.e., oriented along the radial line from the point charge), the angle between them is or .
In this case, the torque . Therefore, the torque on the dipole could be zero.
Since the two charges of the dipole are at different positions, they will experience different electric fields ().
The net force on the dipole is . Thus, the net electric force can never be zero.
The torque on the dipole is given by .
If the dipole is placed such that its dipole moment is parallel or anti-parallel to the electric field (i.e., oriented along the radial line from the point charge), the angle between them is or .
In this case, the torque . Therefore, the torque on the dipole could be zero.