Moving Charges & Magnetism PYQs Set 16 (PDF)

Set 16 of 17 · Questions 451-480 of 499

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Mere Teacher · Previous Year Questions NEET Physics · Moving Charges & Magnetism · Set 16 (Q451-480)
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451. $A solenoid having area A and length ' l' is filled with a material having relative permeability 2. The magnetic energy stored in the solenoid is:$ (1) $\frac{B ^{2} A l}{4 μ _{0}}$ (2) $\frac{B ^{2} A l}{2 μ _{0}}$ (3) $\frac{B ^{2} A l}{μ _{0}}$ (4) $B^{2} Al$ 452. $A coil is placed in magnetic field such that plane of coil is perpendicular to the direction of magnetic field. The magnetic flux through a coil can be changed: (A) By changing the magnitude of the magnetic field within the coil. (B) By changing the area of coil within the magnetic field. (C) By changing the angle between the direction of magnetic field and the plane of the coil. (D) By reversing the magnetic field direction abruptly without changing its magnitude. Choose the most appropriate answer from the options given below:$ (1) $A and B only$ (2) $A, B and C only$ (3) $A, B and D only$ (4) $A and C only$ 453. $A current loop in a magnetic field$ (1) $can be in equilibrium in two orientations, both the equilibrium states are unstable.$ (2) $can be in equilibrium in two orientations, one stable while the other is unstable.$ (3) $experiences a torque whether the field is uniform or non uniform in all orientations.$ (4) $can be in equilibrium in one orientation.$ 454. $A cyclotron is used to accelerate$ (1) $only positively charged particles$ (2) $both positively and negatively charged particles$ (3) $neutron$ (4) $only negatively charged particles.$ 455. $Given below are two statements Statement I: Biot-Savart's law gives us the expression for the magnetic field strength of an infinitesimal current element (Idl) of a current carrying conductor only. Statement II: Biot-Savart's law is analogous to Coulomb's inverse square law of charge q, with the former being related to the field produced by a scalar source, Idl while the latter being produced by a vector source, q. In light of above statements choose the most appropriate answer from the options given below. [NEET 2022]$ (1) $Both Statement I and Statement II are incorrect.$ (2) $Statement I is correct and Statement II is incorrect.$ (3) $Statement I is incorrect and Statement II is correct.$ (4) $Both Statement I and Statement II are correct.$ 456. $Pick out the wrong statement.$ (1) $The gain in the K.E. of the electron moving at right angles to the magnetic field is zero.$ (2) $When an electron is shot at right angles to the electric field, it traces a parabolic path.$ (3) $An electron moving in the direction of the electric field gains K.E.$ (4) $An electron at rest experiences no force in the magnetic field$ 457. $An electron is moving along the positive x-axis. If uniform magnetic field is applied parallel to the negative z-axis, then (A) The electron will experience magnetic force along positive y-axis (B) The electron will experience magnetic force along negative y-axis (C) The electron will not experience any force in magnetic field (D) The electron will continue to move along the positive x-axis (E) The electron will move along circular path in magnetic field Choose the correct answer from the option given below:$ (1) $A and E only$ (2) $C and D only$ (3) $B and E only$ (4) $B and D only$ 458. $In a cyclotron a charged particle$ (1) $speeds up in dee$ (2) $undergoes acceleration all the time$ (3) $slows down within a dee and speeds up between dees$ (4) $speeds up between the dees because of the magnetic field.$ 459. $In a moving coil galvanometer, two moving coils M_{1} and M_{2} have the following particulars: R_{1} = 5Ω, N_{1} = 15, A_{1} = 3.6 \times 10^{- 3} m^{2}, B_{1} = 0.25 T R_{2} = 7Ω, N_{2} = 21, A_{2} = 1.8 \times 10^{- 3} m^{2}, B_{2} = 0.50 T Assuming that torsional constant of the springs are same for both coils, what will be the ratio of voltage sensitivity of M_{1} and M_{2} ?$ (1) $1 : 1$ (2) $1 : 3$ (3) $1 : 2$ (4) $1 : 4$ 460. $Consider a moving coil galvanomenter (MCG): (A) The torsional constant in moving coil galvanometer has dimentions (ML^{2} T^{- 2}) (B) Increasing the current sensitivity may not necessarily increase the voltage sensitivity. (C) If we increase number of turns (N) to its double (2 N), then the voltage sensitivity doubles. (D) MCG can be converted into an ammeter by introducing a shunt resistance of large value in parallel with galvanometer. (E) Current sensitivity of MCG depends inversely on number of turns of coil. Choose the correct answer from the options given below:$ (1) $A, D Only$ (2) $A, B, E Only$ (3) $B, D, E Only$ (4) $A, B Only$ 461. $Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: If Oxygen ion (O^{- 2}) and Hydrogen ion (H^{+}) enter normal to the magnetic field with equal momentum, then the path of O^{- 2} ion has a smaller curvature than that of H^{+} . Reason R: A proton with same linear momentum as an electron will form a path of smaller radius of curvature on entering a uniform magnetic field perpendicularly. In the light of the above statements, choose the correct answer from the options given below$ (1) $Both A and R are true but R is NOT the correct explanation of A$ (2) $A is false but R is true$ (3) $A is true but R is false$ (4) $Both A and R are true and R is the correct explanation of A$ 462. $A long cylindrical conductor with large cross section carries an electric current distributed uniformly over its cross-section. Magnetic field due to this current is :(A) maximum at either ends of the conductor and minimum at the midpoint(B) maximum at the axis of the conductor(C) minimum at the surface of the conductor(D) minimum at the axis of the conductor(E) same at all points in the cross-section of the conductor Choose the correct answer from the options given below:$ (1) $(A), (D) Only$ (2) $(D) Only$ (3) $(E) Only$ (4) $(B), (C) Only$ 463. $Consider a long thin conducting wire carrying a uniform current I. A particle having mass \" \" and charge \" \" is released at a distance \" \" from the wire with a speed along the direction of current in the wire. The particle gets attracted to the wire due to magnetic force. The particle turns round when it is at distance from the wire. The value of is [ is vacuum permeability]$ (1) $a e^{- \frac{4 π m v _{0}}{q μ _{0}}}$ (2) $a [1 - \frac{m v _{0}}{2 q μ _{0} I}]$ (3) $a [1 - \frac{m v}{q μ _{0} I}]$ (4) $\frac{a}{2}$ 464. $A current of 1.5A is flowing through a triangle, of side 9cm each. The magnetic field at the centroid of the triangle is: (Assume that the current is flowing in the clockwise direction.)$ (1) $3 \times 1 0^{- 7} T, outside the plane of triangle$ (2) $23 \times 1 0^{- 7} T, outside the plane of triangle$ (3) $23 \times 1 0^{- 5} T, inside the plane of triangle$ (4) $3 \times 1 0^{- 5} T, inside the plane of triangle$ 465. $As shown in the figure, a current of 2A flowing in an equilateral triangle of side 43 cm. The magnetic field at the centroid O of the triangle is: (Neglect the effect of earth's magnetic field.)$ (1) $43 \times 1 0^{- 4} T$ (2) $43 \times 1 0^{- 5} T$ (3) $3 x 1 0^{- 4} T$ (4) $33 \times 1 0^{- 5} T$ 466. $A conducting wire is in the shape of a regular hexagon which is inscribed inside an imaginary circle of radius R . If a current I flows the wire, the magnitude of magnetic field at the centre of the circle is$ (1) $\frac{μ _{0} I}{2 3 π R}$ (2) $\frac{3 μ _{0} I}{2 π R}$ (3) $\frac{3 μ _{0} I}{2 π R}$ (4) $\frac{3 μ _{0} I}{πR}$ 467. $A particle of mass m and charge q is in an electric and magnetic field given by E = 2 i^+ 3 j^; B = 4 j^+ 6 k^. The charged particle is shifted from the origin to the point P(x = 1; y = 1) along a straight path. The magnitude of the total work done is:$ (1) $5q$ (2) $(2.5)q$ (3) $(0.35) q$ (4) $(0.15)q$ 468. $A straight wire of length 0.5 meter and carrying a current of 1.2 ampere is placed in uniform magnetic field of induction 2 tesla. The magnetic field is perpendicular to the length of the wire. The force on the wire is$ (1) $2.4 N$ (2) $1.2 N$ (3) $3.0 N$ (4) $2.0 N$ 469. $Statement (I): A uniform electric field and a uniform magnetic field are pointed in the same direction. If an electron is projected in the same direction the electron velocity will decrease in magnitude. Statement (II): Two infinite long parallel wires are carrying current in the same direction. The magnetic field at a point midway between the wires is zero. Statement (III): No net force acts on a rectangular coil carrying a steady current when suspended in a uniform magnetic field. Which of the following is correct?$ (1) $Statements I, II and III are true.$ (2) $Statements I and II are true, but statement III is false.$ (3) $Statements II and III are true, but statement I is false.$ (4) $Statements I and III are true, but statement II is false.$ 470. $The magnetic moment of a diamagnetic atom is$ (1) $much greater than one$ (2) $one$ (3) $between zero and one$ (4) $equal to zero$ 471. $Given below are two statements: One is labeled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In an uniform magnetic field, speed and energy remains the same for a moving charged particle. Reason (R): Moving charged particle experiences magnetic force perpendicular to its direction of motion.$ (1) $Both (A) and (R) are true and (R) is the correct explanation of (A)$ (2) $Both (A) and (R) are true but (R) is NOT the correct explanation of (A)$ (3) $(A) is true but (R) is false$ (4) $(A) is false but (R) is true.$ 472. $Among the following, Ampere's circuital law is represented by$ (1) $\oint B \cdot dl = 0$ (2) $\oint B \cdot dl = μ_{0} I$ (3) $\oint B \cdot dl = \frac{μ _{0}}{I}$ (4) $\oint B \cdot dl = μ_{0}$ 473. $A rod with circular cross-section area 2 c m^{2} and length 40 cm is wound uniformly with 400 turns of an insulated wire. If a current of 0.4 A flows in the wire windings, the total magnetic flux produced inside windings is 4 π x10-6Wb. The relative permeability of the rod is (Given: Permeability of vacuum μ_{0} = 4 π \times 1 0^{- 7} N A^{- 2})$ (1) $12.5$ (2) $\frac{32}{5}$ (3) $125$ (4) $\frac{5}{16}$ 474. $Two long parallel conductors S_{1} and S_{2} are separated by a distance 10 cm and carrying currents of 4A and 2A respectively. The conductors are placed along x-axis in X-Y plane. There is a point P located between the conductors (as shown in figure). A charge particle of 3 π coulomb is passing through the point P with velocity v = (2 i + 3 j) m / s; where x & y represents unit vector along x & y axis respectively. The force acting on the charge particle is 4 π \times 1 0^{- 5} (- x i + 2 j) N . The value of x is:$ (1) $2$ (2) $1$ (3) $3$ (4) $-3$ 475. $The magnetic susceptibility negative for$ (1) $paramagnetic and ferromagnetic materials$ (2) $diamagnetic material only$ (3) $paramagnetic material only$ (4) $ferromagnetic material only$ 476. $In which of the following case no force exerted by a magnetic field on a charge?$ (1) $Moving with constant velocity$ (2) $Moving in a circle$ (3) $At rest$ (4) $Moving along a curved path$ 477. $A current loop in a magnetic field:$ (1) $can be in equilibrium in one orientation$ (2) $can be in equilibrium in two orientations, both the equilibrium states are unstable$ (3) $can be in equilibrium in two orientations, one stable while the other is unstable$ (4) $experiences a torque whether the field is uniform or non uniform in all orientate$ 478. $Two infinitely long thin wires are placed at (1 cm, 0 cm) and (2 cm, 0 cm) as shown in the figure. The same current i flows in both the wires in the same direction, say, into the page. Let the magnetic field at the origin due to these wires is B . If B_{0} is the magnitude of the magnetic field if only the wire at (1 cm, 0 cm) was present, then the value of B / B_{0} is$ (1) $3/2$ (2) $2/3$ (3) $½$ (4) $2$ 479. $A particle having a mass of 1 0^{- 2} kg carries a charge of 5 \times 1 0^{- 8} C. The particle is given an initial horizontal velocity of 1 0^{5} m s^{- 1} in the presence of electric field E and magnetic field B. To keep the particle moving in a horizontal direction, it is necessary that (A) B should be perpendicular to the direction of velocity and E should be along the direction of velocity (B) Both B and E should be along the direction of velocity (C) Both B and E are mutually perpendicular and perpendicular to the direction of velocity (D) B should be along the direction of velocity and E should be perpendicular to the direction of velocity. Which one of the following pairs of statements is possible?$ (1) $(A) and (C)$ (2) $(C) and (D)$ (3) $(B) and (C)$ (4) $(B) and (D)$ 480. $A particle having a mass of 10-2 kg carries a charge of 5 \times 10-8 C. The particle is given an initial horizontal velocity of 105 m s^{-1} in the presence of electric field E and magnetic field B . To keep the particle moving in a horizontal direction, it is necessary that (i) should be perpendicular to the direction of velocity and E should be along the direction of velocity (ii) Both B and E should be along the direction of velocity (iii) Both B and E are mutually perpendicular and perpendicular to the direction of velocity. (iv) B should be along the direction of velocity and E should be perpendicular to the direction of velocity Which one of the following pairs of statements is possible$ (1) $(i) and (iii)$ (2) $(iii) and (iv)$ (3) $(ii) and (iii)$ (4) $(ii) and (iv)$