Moving Charges & Magnetism: Class 12 Previous Year Questions

Moving Charges & Magnetism questions asked in CBSE board exams

Repeated questions first. Open the free app to see each question as it appeared in the paper, with its marking scheme.

1.   3. A long straight wire of circular cross-section (radius a) carries a steady current I. The current is uniformly distributed across this cross-section. The magnitude of the magnetic field produced at a point at a distance (a/2) from the axis of the wire w…
   Board 20261 markMCQRepeated: 2023,2026
2. A long straight wire of radius ·a' carries a steady current 'I'. The current is uniformly distributed across its area of cross-section. The ratio of magnitude of magnetic field B at 2 and B, at distance 2a is (a) (b) (c) (d)
   Board 20231 markMCQRepeated: 2023,2026
3. A straight long wire lying along y-axis, carries a current of 1 A along –y direction. The magnetic field due to the conductor at a point (50 cm, 0, 0) will point along. 1 (A) z-axis (B) –z-axis (C) x-axis (D) –x-axis
   Board 20261 markMCQ
4. Derive an expression for the magnetic field B, due to a circular coil of N turns, each of radius r carrying current I, at a distance ‘x’ from the centre along its axis.
   Board 20263 marksshort answer
5. A galvanometer of resistance 27  is converted into an ammeter of range (0 – 10 mA) using a resistance of 3 . The galvanometer will show full scale deflection for a current of about – 1 (A) 10 mA (B) 100 mA (C) 1 mA (D) 3 mA
   Board 20261 markMCQ
6. (i) Define mutual inductance of a pair of coils. Write its SI unit. 3 (ii) A long solenoid of radius R and length L has n turns per unit length. A circular loop of radius r(<R) is placed inside at the centre of the solenoid such that its axis coincides with th…
   Board 20263 marksshort answer
7.  29. A galvanometer is used to detect or/and measure small currents in an electrical circuit. It essentially works on the fact that a current-carrying coil experiences a deflecting torque when placed in a magnetic field. This deflection in the coil can be mea…
   Board 20264 marksshort answer
8. A wire of length L is bent round into (i) a square coil having N turns and (ii) a circular coil having N turns. The coil in both cases is free to turn about a vertical axis coinciding with the plane of the coil, in a uniform, horizontal magnetic field and carr…
   Board 20262 marksshort answer
9. A magnet held vertically, with its north pole down is dropped along the axis of a closed solenoid placed vertically on a table. If the observer looks down from the top, 1 (A) the induced current will flow in the anticlockwise direction. (B) the induced current…
   Board 20261 markMCQ
10. Using Biot-Savart law, derive expression for the magnetic field (B) due to a circular current carrying loop at a point on its axis and hence at its centre.
    Board 20253 marksshort answer
11. A 1 cm segment of a wire lying along x-axis carries current of 0.5 A along +x direction. A magnetic field B = (0.4 mT) } + (0.6 mT) K is switched on, in the region. The force acting on the segment is (A)(2) + 3k) mN (B) (-3 + 2k) ·N (C) (6j + 4k) mN (D)(-4j + …
    Board 20251 markMCQ
12. A coil has 100 turns, each of area 0.05 m2 and total resistance 1.5 Q. It is inserted at an instant in a magnetic field of 90 mT, with its axis parallel to the field. The charge induced in the coil at that instant is : (A) 3.0 mC (B)0.30 C (C)0.45 C (D) 1.5 C
    Board 20251 markMCQ
13. A 1 cm straight segment of a conductor carrying 1 A current in x direction lies symmetrically at origin of Cartesian coordinate system. The magnetic field due to this segment at point (lm, lm, O) is (A) 1.0 × 10-9 T (B) -1.0 × 10-9 T 5.0 5.0 (C) ×10-10 T (D) ×…
    Board 20251 markMCQ
14. (a) () A proton moving with velocity V in a non-uniform magnetic field traces a path as shown in the figure. The path followed by the proton is always in the plane of the paper. What is the direction of the magnetic field in the region near points P, Q and R ?…
    Board 20255 markslong answer
15. Assertion (A) : The deflection in a galvanometer is directly proportional to the current passing through it. Reason(R) : The coil of a galvanometer is suspended in a uniform radial magnetic field.
    Board 20251 markAssertion-Reason
16. (a) Show that the energy required to build up the current I in a coil of (b) Considering the case of magnetic field produced by air-filled current carrying solenoid, show that the magnetic energy density of a B2
    Board 20253 marksshort answer
17. You are required to design an air-filled solenoid of inductance O.016 H having a length 0.8l m and radius 0.02 m. The number of turns in the solenoid should be (A)2592 (B) 2866 (C) 2976 (D) 3140 Page 5 of 24 ·· 6· = sin t i = o sin (ot + ) (A) (B) io Vo cos · …
    Board 20251 markMCQ
18. A loop carrying a current I clockwise is placed in x y plane, in a uniform magnetic field directed along z-axis. The tendency of the loop will be to : (A) move along x-axis (B) move along y-axis (C) shrink (D) expand
    Board 20241 markMCQ
19. Xmo H$Um|, {OZHo$ Ðì`_mZ m1 Am¡a m2 h¢, Ho$ {bE Xo ~«m°½br Va§JX¡¿`© H$mo K 1 Ho$ \$bZ Ho$ ê$n _| AmaoI _| Xem©`m J`m h¡ & `hm± K J{V_mZ H$Um| H$s D$Om© h¡ & K 1 (H$) ? (I) BZ_| go H$m¡Z-gm H$U A{YH$ ^mar h¡ ? (J) \$ {H$gr µ\$moQ>m°Z Ho$ {bE ^r d¡Y h¡ ? àË`oH$…
    Board 20243 marksshort answer
20. A 10 cm long wire lies along y-axis. It carries a current of 1.0 A in positive y-direction. A magnetic field B = (5 mT)^j (8 mT) ^k exists in the region. The force on the wire is : (A) (0·8 mN)^i (B) (0·8 mN)^i (C) (80 mN)^i (D) (80 mN)^i 6 6. à{VamoY G Ho$ {H…
    Board 20241 markMCQ

Practise all 44 Moving Charges & Magnetism questions with answers →

Other Class 12 Physics chapters

Frequently asked questions