Match List-I with List-II for the magnetic field lines of a bar magnet.
| List-I | List-II |
|---|---|
| (A) Tangent to a magnetic field line at a point | (I) Direction of the net field \(B\) |
| (B) Number of field lines crossing per unit area | (II) Magnetic monopoles do not exist |
| (C) Field lines do not intersect | (III) Strength of the field \(B\) |
| (D) Field lines form continuous closed loops | (IV) The field \(B\) has only one direction at any point |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A)-(I), (B)-(III), (C)-(IV), (D)-(II)
(A) Tangent to a magnetic field line at a point — This matches (I). The tangent shows the direction of the net field \( B \) at that point.
(B) Number of field lines crossing per unit area — This matches (III). Where the lines are crowded, the field is stronger.
(C) Field lines do not intersect — This matches (IV). At a crossing point the field would have two directions, which is not possible.
(D) Field lines form continuous closed loops — This matches (II). There are no isolated poles for the lines to start or end on.
NCERT (2026-27):
The magnetic field lines – “(ii) The tangent to the field line at a given point represents the direction of the net magnetic field B at that point.”
The magnetic field lines – “(iii) The larger the number of field lines crossing per unit area, the stronger is the magnitude of the magnetic field B. …”
The magnetic field lines – “(iv) The magnetic field lines do not intersect, for if they did, the direction of the magnetic field would not be unique at the point of intersection. …”
Points to Ponder – “3. A consequence of the fact that magnetic monopoles do not exist is that the magnetic field lines are continuous and form closed loops. …”