In-text Questions — Field Around a Straight Conductor — Magnetic Effects of Electric Current

1. 12 marksNCERT Cl-10 Science, In-text Qs after §12.2.2, Q1

   Draw magnetic field lines around a bar magnet.

   Hint. Outside the magnet the lines go one way; inside, they have to complete the loop the other way.

   Step 1 — Outside the magnet. Field lines emerge from the north pole, curve around through the surrounding space, and enter the south pole.

   Step 2 — Inside the magnet. Since field lines form closed loops, they continue inside the magnet from the south pole back to the north pole, closing the loop.

   Step 3 — Density near the poles. The lines are drawn closer together near the poles, where the field is strongest, spreading out further away.

   ✦ Answer: Closed loops emerging from the north pole, curving through the space around the magnet, entering the south pole, and continuing inside the magnet from south back to north — denser near the poles.

   Where students slip. Drawing field lines that stop at the magnet's surface — field lines never have a start or end; they must form complete closed loops, continuing through the inside of the magnet.

2. 22 marksNCERT Cl-10 Science, In-text Qs after §12.2.2, Q2

   List the properties of magnetic field lines.

   Hint. Think about their shape, their direction convention, their spacing, and whether they can cross.

   Step 1 — Shape and direction. Field lines are closed curves, emerging from the north pole and merging at the south pole outside the magnet (continuing north pole to south pole inside it).

   Step 2 — What the tangent gives. The direction of the magnetic field at any point is given by the tangent to the field line at that point.

   Step 3 — Spacing and crossing. Field lines are closer together where the field is stronger, and two field lines never intersect each other.

   ✦ Answer: Field lines are closed curves running from north to south outside a magnet (and south to north inside); the field's direction at a point is the tangent there; lines are closer where the field is stronger; and no two field lines ever cross.

   Where students slip. Omitting the 'never intersect' property — this is one of the most frequently tested properties on its own (see the next question) and is easy to leave out of a general list.

3. 32 marksNCERT Cl-10 Science, In-text Qs after §12.2.2, Q3

   Why don't two magnetic field lines intersect each other?

   Hint. Think about what a crossing point would imply about the field's direction there.

   Step 1 — Consider what an intersection would mean. At any point where two field lines crossed, the tangent to each line would give a different direction for the magnetic field at that single point.

   Step 2 — Recall that the field has only one direction at any point. Since the magnetic field at a given point has one definite direction, it cannot point two ways at once.

   Step 3 — Conclude. So field lines never intersect, since an intersection would require the impossible: two different field directions at the same point.

   ✦ Answer: Two field lines can't cross because the field has only one direction at any given point — an intersection would imply two directions there, which is impossible.

   Where students slip. Explaining this in terms of the lines 'getting in each other's way' physically — field lines aren't physical objects; the real reason is that the field's direction at any point must be single-valued.

Solutions written by the tuition.in editorial team and checked against the NCERT Class 10 Science textbook, Reprint 2026-27 (jesc112.pdf) — five in-text question sets (12 questions total) plus one end-of-chapter Exercise (9 questions, not 18 as some older manifests claim). The electric motor, electromagnetic induction and electric generator have been removed from this chapter entirely (confirmed by full-text search) — they are named once as example devices, with no construction/working explained, and don't appear in the chapter's own 'What you have learnt' summary. One exercise question (Q7(iii)) still references induced current despite this; it is answered using Fleming's right-hand rule, flagged accordingly.. Questions are referenced from the NCERT textbook for identification.