Tiêu đề 06. ELECTROMAGNETIC INDUCTION(H).pdf ✅

NEET REVISION 06. ELECTROMAGNETIC INDUCTION(H) NEET REVISION Date: March 18, 2025 Dura on: 1:00:00 Total Marks: 180 INSTRUCTIONS INSTRUCTIONS PHYSICS 1. Find the mutual inductance in the arrangement, when a small circular loop of wire of radius ' ' is placed inside a large square loop of wire of side . The loops are coplanar and their centres coincide [Q358525] (1) (2) (3) (4) 2. A metallic rod of length ' ' is tied to a string of length and made to rotate with angular speed on a horizontal table with one end of the string fixed . If there is a vertical magnetic field ' ' in the region, the e.m.f. induced across the ends of the rod is : [Q358444] (1) (2) (3) (4) 3. Wire with negligible resistance slides on the three rails with . If the current in resistance when switch is connected to posi‐ tion 1 is and when the switch is at position 2 the current becomes . Find the ratio . [Q358483] (1) 0.5 (2) 0.9 (3) 0.3 (4) 0.7 4. The graph shows the variation in magnetic flux with time through a coil. Which of the state‐ ment given below is not correct? [Q358635] (1) There is a change in the direction as well as magnitude of induced emf between and (2) The magnitude of the induced emf is maximum between and (3) There is a change in the direction as well as magnitude of induced emf between and (4) The induced emf is not zero at 5. If a resistance less rod is moving with constant velocity in a constant magnetic field. Then di‐ rection of current and in resistance and respectively is : [Q358678] (1) clockwise, Anticlockwise (2) Anticlockwise, Clockwise (3) and both clockwise (4) and both Anticlockwise R L(L >> R) M = 2√2μ0R 2 L M = √2μ0R 2 L M = √2μ0R L2 M = 2√2μ0R L2 l 2l ω B 2Bωl 2 2 3Bωl 2 2 4Bωl 2 2 5Bωl 2 2 PQ 5 cm/sec 10 Ω S i1 i2 i1 i2 φ(t) A D B C B D B v I1 I2 R1 R2 I1 → I2 → I1 → I2 → I1 I2 I1 I2
NEET REVISION 6. A uniform magnetic field of induction is con‐ fined to a cylindrical region of radius. . The magnetic field isincreasing at a constant rate . An electron placed at the point on the periphery of the field, experience an ac‐ celeration [Q358498] (1) towards left (2) towards left (3) towards right (4) Zero 7. A coil of circular cross - section having 1000 turns and face area is placed with its axis parallel to a magnetic field which decreases by in . The e.m.f. induced in the coil is :- [Q358623] (1) (2) (3) (4) 8. It is desired to measure the magnitude of field between, the poles of a powerful loudspeaker magnet. A small flat search coil of area with 20 closely wound turns is positioned normal to field direction, and then quickly snatched out of the field region. The total charge flown in the coil (measured by a ballistic galvanometer con‐ nected to the coil) is . The resistance of the coil and the galvanometer is . The field strength of the magnet would be [Q358697] (1) (2) (3) (4) 9. Two coaxial solenoids are made by winding a thin insulated wire over a pipe of cross sectional area and length . If one of the solenoids has 300 turns and the other 400 turns, their mutual inductance is [Q358521] (1) (2) (3) (4) 10. An ideal coil of is connected in series with a resistance of and a battery of . Two seconds after the connection is made, the current flowing (in ) in the circuit is [Q358370] (1) (2) (3) (4) 11. The figure shows a square loop of side which is connected to a network of resistances. The whole setup is moving towards right with a constant speed of . At some instant, a part of is in a uniform magnetic field of , perpendicular to the plane of loop. If the resis‐ tance of is , the current in the loop at that instant is found out to be [Q358432] (1) 3.16 (2) 2.34 (3) 1.25 (4) 5.62 12. Two coils have a mutual inductance . The current changes in the first coil according to equation . where, and The maximum value of emf in the second coil is [Q358528] (1) (2) (3) (4) 13. A conducting rod of length is moving with a uniform speed in a uniform magnetic field directed into the paper. A capacitor of capacity is connected as shown in figure. Then [Q358492] (1) (2) and (3) and (4) Charge stored in the capacitor increase expo- nentially with time 14. A circular loop of radius is moved with a ve‐ locity as shown in the diagram. The work needed to maintain its velocity constant is : [Q358433] (1) (2) (3) (4) Zero B R dB/dt Ts −1 P 1 2 eR m dB dt eR m dB dt 1 2 eR m dB dt 4 cm2 10 −2 Wb m−2 0.01 s 4 mV 200 mV 0.4 mV 400 mV 2.0 cm2 10 mC 1Ω 3.7 T 2.5 T 5.2 T 7.4 T A = 10 cm2 20 cm (μ0 = 4π × 10 −7 Tm/A) 2.4π × 10 −4 H 2.4π × 10 −5 H 4.8π × 10 −4 H 4.8π × 10 −5 H 10 H 5Ω 5 V A e e −1 1 − e −1 1 − e L 5 cm 1cms −1 L 1T L 2.7 Ω N × 10 −4 A Find N. [ Take = 1.3] 4 3 0.005 H I = I0 sin ωt I0 = 10 A ω = 100π rads −1 . 2πV 5πV πV 4πV PQ L = 1.0 m v = 2.0 ms −1 B = 4.0 T C = 10μF qA = 0 = qB qA = +80μC qB = −80μC qA = −80μC qB = +80μC r v μ0ivr 2π(a + r) ln( ) μ0 ivr 2πa 2r + a a μ0ivr 2πa
NEET REVISION 15. A structure formed from two straight conduct‐ ing rods forming a right angle, is placed in a uni‐ form magnetic field with is directed out of the page. A straight conducting bar in con‐ tact with the structure, starts at the vertex at time and moves with a constant velocity of along them. The around the trian‐ gle at that time is [Q358455] (1) (2) (3) (4) 16. In the circuit of figure, the battery emf is , the resistance is , and the capacitance is . The switch is closed for a long time interval, and zero potential difference is mea‐ sured across the capacitor. After the switch is opened, the potential differ‐ ence across the capacitor reaches a maximum value of The value of the inductance is [Q358600] (1) (2) (3) (4) 17. A magnetic field confined in a cylindrical re‐ gion of radius is changing at rate . conducting semi-infinite rod is placed as shown in the figure. Find the emf induced across the rod. [Q358499] (1) (2) (3) (4) 18. The figure shows four wire loops, with edge lengths of either or . All of four loops will move through a region of uniform magnetic field (directed out of page) at the same constant ve‐ locity. Rank the four loops according to the max‐ imum magnitude of the e.m.f. induced as they move through the field, greatest first [Q358468] (1) (2) (3) (4) 19. An inductor and a resistor are connected in series to a bat‐ tery of e.m.f in a circuit shown. The key has been kept closed for a long time. Then at is opened and key is closed simul‐ taneously. At , the current in the circuit will be: [Q358372] (1) (2) (3) (4) 20. An aircraft with a wing span of flies with a speed of in the eastward direction at a constant altitude in the northern hemisphere, where the vertical component of earth's magnetic field is The that develops between the tips of the wing is [Q358469] (1) (2) (3) (4) 21. A solenoid long is made by winding 2000 loops of wire on an iron rod whose cross- section is . If the relative permeability of the iron is 600 , what is the self inductance of the solenoid? [Q358592] (1) (2) (3) (4) 22. A closed coil having 20 turns, area of cross-sec‐ tion and resistance are connected to a ballistic galvanometer of resistance . If the normal of the coil is inclined at to the direction of a magnetic field of intensity , the coil is quickly pulled out of the field to a region of zero magnetic field, the charge passed through the galvanometer is [Q358695] (1) (2) (3) (4) 23. In the following circuit, the switch is closed at . Initially, there is no current in inductor. B = 0.40 T t = 0 5.0 m/s emf t = 4.0 s 40 V 70 V 50 V 80 V 50 V 200 Ω 1.0 μF S 100 V 130 mH 160 mH 190 mH 150 mH R = α dB dt A πR 2α 4 πR 2α πR2α 2 2πR2α L 2L B→ (εc = εd) < (εa = εb) (εc = εd) > (εa = εb) εc > εd > εa > εb εc < εd < εa < εb (L = 0.03H) (R = 0.15 kΩ) 15 V k1 t = 0, K1 K2 t = 1 ms (e 5 ≅150) 67 mA 6.7 mA 0.67 mA 100 mA 40 m 1080 kmh −1 1.75 × 10 −5 T. emf 0.15 V 0.46 V 0.21 V 0.71 V 30 cm 1.5 cm2 1.5H 2.5H 3.5H 0.5H 1 cm2 2 ohms 30 ohms 60 ∘ 1.5 Wb/m2 50 μC 30 μC 70 μC 40 μC t = 0