Title 04. MOVING CHARGES AND MAGNETISM.pdf ✅

04. MOVING CHARGES AND MAGNETISM NEET PREPARATION (MEDIUM PHYSICS PAPER) Date: March 12, 2025 Dura on: 1:00:00 Total Marks: 180 INSTRUCTIONS INSTRUCTIONS PHYSICS 1. A long solenoid of 50 length having 100 turns carries a current of 2.5 . the magnetic field at the centre of the solenoid is: (1) (2) (3) (4) 2. An electron is allowed to move with constant ve‐ locity along the axis of current carrying straight solenoid. (A) The electron will experience magnetic force along the axis of the solenoid. (B) The electron will not experience magnetic force. (C) The electron will continue to move along the axis (D) The electron will be accelerated along the axis of the solenoid. (E) The electron will follow parabolic path inside the solenoid. Choose the correct answer from the options given below. (1) B and E only (2) B and C only (3) A and D only (4) B, C and D only 3. An equilateral triangle is made by uniform wires , , . A current enters at and leaves from the mid point of . If the lengths of each side of the triangle is . The magnetic field at the centroid of the triangle is (1) (2) (3) (4) Zero 4. A wire carrying a current along the positive axis has length . It is kept in a magnetic field . The magnitude of the magnetic force acting on the wire is: (1) (2) (3) (4) 5. A rectangular loop carrying a current is placed in a uniform magnetic field . The area enclosed by the loop is . If there are turns in the loop, the torque acting on the loop is given by (1) (2) (3) (4) 6. Consider a moving charged particle in a region of magnetic field. Which of the following are correct? I. If is parallel to , then path of particle is spiral. II. If is perpendicular to , then path of particle is a circle. III. cm A (μ0 = 4π × 10 −7TmA−1 ) 3.14 × 10 −4 T 6.28 × 10 −5 T 3.14 × 10 −5 T 6.28 × 10 −4 T AB BC CA I A BC L B O ( ) μ0 4π 4I L ( ) μ0 4π 2I L ( ) μ0 2π 4I L I x− L B→ = (2^i + 3^j − 4 ^k)T √5 IL 5 IL √3 IL 3 IL i B A n niA→ × B→ niA→ ⋅ B→ (iA→ × B→) 1 n (iA→ ⋅ B→) 1 n v B v B
If has a component along , then path of parti‐ cle is helical. IV. If is along , then path of the particle is a circle. (1) I and II (2) II and III (3) III and IV (4) IV and I 7. The magnetic field due to a current carrying cir‐ cular loop of radius 3 at a point on the axis at a distance of 4 from the centre is . What will be its value at the centre of the loop? (1) (2) (3) (4) 8. A straight wire carrying current is turned into a circular loop. If the magnitude of magnetic mo‐ ment associated with it in unit is , the length of wire will be (1) (2) (3) (4) 9. Statement A : The energy of a charged particle moving in a uniform magnetic field does not change. Statement B : Work done by the magnetic field on a charged particle is zero. (1) Statement A is correct but Statement B is incorrect. (2) Statement A is in- correct but Statement B is correct. (3) Both statements are correct. (4) Both Statements are incorrect. 10. Three long, straight parallel wires carrying cur‐ rent, are arranged as shown in figure. The force experienced by a 25 length of wire is (1) (2) (3) zero (4) 11. A proton, a deutron and an -particle enter a magnetic field with same velocity. The ratio of the radii of circular paths is (1) (2) (3) (4) 12. A straight conductor of mass and carrying a current is hinged at one end and placed in a plane perpendicular to the magnetic field of in‐ tensity as shown in the figure. At any moment if the conductor is left free, then the angular ac‐ celeration of the conductor will be (Assume gravity free region) (1) (2) (3) (4) 13. A moving coil galvanometer has 100 turns and each turns has an area of . The magnetic field produced by the magnet is . The de‐ flection in the galvanometer coil is when a current of 10 is passed through it. The torsional constant of the spiral spring is (1) (2) (3) (4) 14. A charged particle moving with velocity enters perpendicular to a magnetic field . It moves in circular path of radius 2 then charge per unit mass is: (1) (2) (3) (4) 15. In the product For and and What will be the complete expression for ? (1) (2) (3) (4) 16. Assertion : A direct current flowing through a metallic rod produces magnetic field both inside and outside. Reason : There is no flow of charge carries inside the rod. v B v B cm cm 54μT 200μT 250μT 125μT 75μT i MKS M 4π M √ 4πM i √ 4πi M Mπ i cm C 10 3 N 2.5 × 10 3 N 1.5 × 10 −3 N α 1 : 2 : 2 1 : 2 : 1 2 : 1 : 1 1 : 1 : 2 m ′ i ′ B 3i 3mB 3iB 2 m 3iB 3 m 3B 2m 2 cm2 0.01 T 0.05 rad mA 4 × 10 −5Nmrad −1 3.0 × 10 −4Nmrad −1 7 × 10 −7Nmrad−1 5 × 10 −6Nmrad−1 4 × 10 6 ms−1 B = 2Wbm−2 a cm 10 2Ckg−1 10 3Ckg−1 10 4Ckg −1 10 8Ckg −1 F→ = q(v→ × B→) = qv→ × (B^i × B^j × B0k^) q = 1 v→ = 2^i + 4^j + 6 ^k F→ = 4^i − 20^j + 12k^ B→ −6^i − 6→j − 8k^ 8^i + 8→j − 6k^ 6^i + 6^j − 8k^ −8^i − 8 →j − 6k^

25. Two parallel wires 1 apart carry current of 1 and 3 respectively in opposite directions. The force per unit length acting between these two wires is (1) attractive (2) attractive (3) repulsive (4) repulsive 26. Two similar coils of radius are lying concen‐ trically with their planes at right angles to each other. The currents flowing in them are and 2 , respectively. The resultant magnetic field induc‐ tion at the centre will be (1) (2) (3) (4) 27. A solenoid of 1.5 length of 4.0 diameter possesses 10 turns/ . A current of 10 is flow‐ ing through it. The magnetic induction at axis in‐ side the solenoid is: (1) (2) (3) (4) 28. Full scale deflection current for galvanometer is . For making its range upto . Find the required shunt (Resistance of Galvanometer is . (1) (2) (3) (4) 29. A straight conductor carrying current . If the magnetic field at a distance is 0.4 , then mag‐ netic field at a distance 2 will be: (1) 0.4 (2) 0.1 (3) 0.8 (4) 0.2 30. A direct current I flows a long the length of an infinitely long straight thin walled pipe, then the magnetic field is (1) Uniform through- out the pipe but not zero (2) Zero only along the axis of the pipe (3) Zero at any point inside the pipe (4) Maximum at th centre and minimum at the edges. 31. Two particles and having equal charges af‐ ter being accelerated through same potential dif‐ ference enter a region of uniform magnetic field and describe a circular paths of radii and respectively. The ratio of the mass of to that of is (1) (2) (3) (4) 32. A electron having charge and mass is moving with speed in a magnetic field in a circular orbit. The force acting on electron and the radius of the circular orbit will are respectively. (1) (2) (3) (4) 33. and are two infinitely long straight parallel conductors. is another straight conductor of length 1 kept parallel to and as shown in the figure. Then, the force experienced by is (1) towards equal to (2) towards equal to (3) towards equal to (4) towards equal to 34. An electron moves straight inside a charged parallel plate capacitor of uniform surface charge density . The space between the plates is filled with constant magnetic field of induction , as shown in the figure. Neglecting gravity, the time of straight line motion of the electron in the ca‐ pacitor is (1) (2) (3) (4) m A A 6 × 10 −7 N m−1 6 × 10 −5 N m−1 6 × 10 −7 N m−1 6 × 10 −5 N m−1 R I I μ0I R μ0I 2R √5μ0I 2R 3μ0I 2R m cm cm A 4π × 10 −3 T 2π × 10 −5 T 2π × 10 −3G 2π × 10 −5G 1 mA 10 A 1000Ω 1Ω 10Ω 0.3Ω 0.1Ω I r T r T T T T X Y r1 r2 x y r1 r2 √ r1 r2 [ ] 2 r2 r1 [ ] 2 r1 r2 1.6 × 10 −19C 9 × 10 −31 kg 4 × 10 6 ms −1 2 × 10 −1 T 12.8 × 10 −13 N, 1.1 × 10 −5 m 1.28 × 10 −14 N, 1.1 × 10 −3 m 1.28 × 10 −13 N, 1.1 × 10 −3 m 1.28 × 10 −13 N, 1.1 × 10 −4 m A B C m A B C A 3.6 × 10 −5 N B 2.4 × 10 −5 N A 2.4 × 10 −5 N B 3.6 × 10 −5 N σ B σ ε0 B ε0/B σ ε0 B σ σ ε0l B