JEE Main Physics: Electric field lines Practice Questions
15 free multiple-choice questions on Electric field lines (Electricity and Magnetism) for JEE Main Physics, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more JEE Main questions in the app →Q1. Consider a region of space containing a net charge. How do the electric field lines behave around this net charge?
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Correct answer: C — They start from the net charge and spread out
Field lines originate from positive charge and terminate on negative charge. For a net charge, the lines flow away from positive charges and towards negative charges, spreading out from the net distribution.
Q2. If an electric field is directed horizontally, what is the orientation of the corresponding electric field lines?
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Correct answer: D — Horizontally at an angle
Electric field lines are always perpendicular to the surface they are drawn on, and the lines themselves represent the direction of the field. If the field is horizontal, the lines are horizontal.
Q3. If two electric field lines are drawn, what does the distance between them indicate about the electric field intensity in that region?
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Correct answer: B — The field intensity is inversely proportional to the distance
The density or spacing between electric field lines is directly proportional to the magnitude of the electric field at that point. Closer lines indicate a stronger field.
Q4. If two electric field lines are drawn, they represent the direction of the force that a positive test charge would experience when moved through that region. This direction is:
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Correct answer: C — parallel to the line segment connecting the points
The direction of the electric field (E⃗) is tangent to the field lines, which corresponds to the direction of the force on a positive charge.
Q5. Electric field lines represent the direction of the force experienced by a small positive test charge placed at that point. If two field lines are drawn emanating from a charge, the force on a positive charge placed along the direction of the line is:
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Correct answer: D — Directed away from the charge
The electric field points in the direction of the force on a positive test charge. Therefore, the force is directed along the direction of the electric field line.
Q6. Electric field lines always originate from which region in a static electric field?
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Correct answer: A — Region where electric field is zero
Electric field lines originate from positive charges and terminate on negative charges, defining the direction of the force exerted by the field. They generally emanate from positive sources.
Q7. Electric field lines are used to represent the direction of the electric field. The direction of the electric field at any point is given by the direction of the field lines. What physical quantity do these lines represent?
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Correct answer: D — Electric Force
Electric field lines visually represent the direction and magnitude of the electric field (E) at every point in space. The electric force experienced by a charge is in the direction of the electric field.
Q8. In a region where the electric field lines are drawn, what is the physical implication of lines converging towards a point?
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Correct answer: A — The electric field strength is increasing
Converging field lines indicate that the electric field strength is increasing as one approaches that point.
Q9. Electric field lines are always perpendicular to the surface on which they are drawn. If we draw electric field lines for a point charge, what is the nature of the field lines around that charge?
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Correct answer: D — Concentric
For a point charge, the electric field lines are radially outward (or inward) and are perpendicular to the surface at any point, indicating a radial symmetry.
Q10. The density of electric field lines is proportional to the magnitude of the electric field. If two field lines are very close together, what does it imply about the electric field in that region?
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Correct answer: D — The electric field is large
The density of field lines is proportional to the magnitude of the field strength (E). Closer lines indicate a stronger electric field in that region.
Q11. In a region where electric field lines are drawn, the density of the field lines is proportional to the magnitude of the electric field. This relationship is primarily used to determine:
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Correct answer: D — the magnitude of the electric field
The density of electric field lines is proportional to the magnitude of the electric field (E⃗) in that region.
Q12. In a region where the electric field is uniform and constant, what is the configuration of the electric field lines?
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Correct answer: D — They are parallel and equally spaced
In a uniform electric field, the field lines must be parallel to each other and equally spaced, as the field magnitude does not change with position.
Q13. In a configuration of electric field lines, if a region of space is defined such that the lines entering it do not exit it, what does this imply about the net charge distribution within that region according to Gauss's Law visualization?
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Correct answer: D — The net charge inside is zero
Gauss's Law states that the flux emerging out of a closed surface is proportional to the enclosed charge. If field lines enter a region and do not exit (implying a closed configuration, even if not explicitly drawn as a surface), the net enclosed charge responsible for that flux change must be zero, assuming the field is sourced by charges.
Q14. Two electric field lines are drawn. If the lines are parallel and equally spaced, what conclusion can be drawn about the electric field magnitude in the region between them?
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Correct answer: B — The electric field magnitude is constant between the lines.
If field lines are parallel and equally spaced, it means the field is uniform across the separation distance. The magnitude of the field lines represents the field strength, so equal spacing implies a constant electric field magnitude in that region.
Q15. If an electric field vector is directed along a line segment, the force experienced by a small positive test charge placed at that point will be in the direction of the field lines. If the field lines point downwards, the force on a positive charge placed there will be:
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Correct answer: A — Downwards
The force experienced by a positive test charge is in the direction of the electric field lines. If the field lines point downwards, the force is downwards.
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