Magnetism & Matter PYQs Set 4 (PDF)

Set 4 of 6 · Questions 91-120 of 176

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Mere Teacher · Previous Year Questions JEE Main Physics · Magnetism & Matter · Set 4 (Q91-120)
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91. $Given below are two statements: one is labelled as Assertion (A)and the other is labelled as Reason (R). Assertion (A): Magnetic monopoles do not exist. Reason (R): Magnetic field lines are continuous and form closed loops. In the light of the above statements, choose the most appropriate answer from the options given below:$ (1) $Both (A) and (R) are correct and (R) is the correct explanation of (A)$ (2) $(A) is not correct but (R) is correct$ (3) $(A) is correct but (R) is not correct$ (4) $Both (A)and (R) are correct but (R) is not the correct explanation of (A)$ 92. $If relative permeability of iron is 5500, then its susceptibility is$ (1) $5500 \times 10^{7}$ (2) $5500 \times 10^{- 7}$ (3) $5501$ (4) $5499$ 93. $The magnetic susceptibility is negative for [NEET 2016]$ (1) $paramagnetic material only$ (2) $ferromagnetic material only$ (3) $paramagnetic and ferromagnetic materials$ (4) $diamagnetic material only$ 94. $Given below are two statements: Statement-I: Susceptibilities of paramagnetic and ferromagnetic substances increase with decrease in temperature. Statement-II: Diamagnetism is a result of orbital motions of electrons developing magnetic moments opposite to the applied magnetic field. Choose the Correct answer from the options given below: -$ (1) $Both statement -1 and statement -II are true.$ (2) $Both statement -1 and Statement - II are false.$ (3) $Statement - I is true but statement - II is false.$ (4) $Statement-I is false but Statement-II is true.$ 95. $The susceptibility of a paramagnetic material is 99. The permeability of the material in Wb/A-m is: [Permeability of free space μ_{0} = 4 π \times 1 0^{- 7} Wb / A - m]$ (1) $4 π \times 1 0^{- 7}$ (2) $4 π \times 1 0^{- 4}$ (3) $4 π \times 1 0^{- 5}$ (4) $4 π \times 1 0^{- 6}$ 96. $The space inside a straight current carrying solenoid is filled with a magnetic material having magnetic susceptibility equal to 1.2 x . What is fractional increase in the magnetic field inside solenoid with respect to air as medium inside the solenoid?$ (1) $1.2 x 1 0^{- 5}$ (2) $1.2 x 1 0^{- 3}$ (3) $1.8 x 1 0^{- 3}$ (4) $2.4 x 1 0^{- 5}$ 97. $Electromagnets are made of soft iron because soft iron has$ (1) $high susceptibility and low retentivity$ (2) $low susceptibility and high retentivity$ (3) $low susceptibility and low retentivity$ (4) $high susceptibility and high retentivity$ 98. $A 250‐turn rectangular coil of length 2.1 cm and width 1.25 cm carries a current of 85 μA and subjected to a magnetic field of strength 0.85 T . Work done for rotating the coil by 18 0^{0} against the torque is$ (1) $4.55 μ J$ (2) $2.3 μ J$ (3) $1.15 μ J$ (4) $9.1 μ J$ 99. $If the magnetic dipole moment of an atom of diamagnetic material, paramagnetic material and ferromagnetic material are denoted by μ_{d}, μ_{p} and μ_{f} respectively, then$ (1) $μ_{d} = 0 and μ_{p} \neq = 0$ (2) $μ_{d} \neq = 0 and μ_{p} = 0$ (3) $μ_{p} = 0 and μ_{f} \neq = 0$ (4) $μ_{d} \neq = 0 and μ_{f} \neq = 0.$ 100. $Two bar magnets having same geometry with magnetic moments M and 2M, are firstly placed in such a way that their similar poles are in same side then its time period of oscillation is T_{1} . Now the polarity of one of the magnet is reversed then time period of oscillation is T_{2}, then$ (1) $T_{1} < T_{2}$ (2) $T_{1} = T_{2}$ (3) $T_{1} > T_{2}$ (4) $T_{2} = \infty$ 101. $A paramagnetic sample shows a net magnetisation of 6 A / m when it is placed in an external magnetic field of 0.4 T at a temperature of 4 K . When the sample is placed in an external magnetic field of 0.3 T at a temperature of 24 K, then the magnetisation will be$ (1) $1 A / m$ (2) $0.75 A / m$ (3) $4 A / m$ (4) $2.25 A / m$ 102. $Magnetic susceptibility (χ) for a paramagnetic and diamagnetic materials is respectively$ (1) $small, positive and small, positive$ (2) $large, positive and small, negative$ (3) $small, positive and small, negative$ (4) $large, negative and large, positive.$ 103. $A short bar magnet placed with its axis at 45^{\circ} with a uniform external magnetic field of 28.3 \times 10^{- 3} T experiences a torque of magnitude equal to 3.6 \times 10^{- 5} J . The magnitude of magnetic moment of the magnet is nearly$ (1) $1.8 \times 10^{- 3} J T^{- 1}$ (2) $1.2 \times 10^{- 3} J T^{- 1}$ (3) $2.4 \times 10^{- 3} J T^{- 1}$ (4) $1.6 \times 10^{- 3} J T^{- 1}$ 104. $A vibration magnetometer placed in magnetic meridian has a small bar magnet. The magnet executes oscillations with a time period of 2 sec in earth’s horizontal magnetic field of 24 microtesla. When a horizontal field of 18 microtesla is produced opposite to the earth’s field by placing a current carrying wire, the new time period of magnet will be$ (1) $1 s$ (2) $2 s$ (3) $3 s$ (4) $4 s$ 105. $An iron rod is placed parallel to magnetic field of intensity 2000 A / m . The magnetic flux through the rod is 6 \times 10^{- 4} Wb and its cross-sectional area is 3 cm^{2} . The magnetic permeability of the rod in Wb / A - m is$ (1) $10^{- 1}$ (2) $10^{- 2}$ (3) $10^{- 3}$ (4) $10^{- 4}$ 106. $If B is magnetic field and q is the charge then the following represents the Gauss's law of magnetism$ (1) $\int B \cdot d s = 0$ (2) $\int B \cdot d s = q$ (3) $\int B \cdot d s = 4 π$ (4) $\int B \cdot d s = μ_{0} q$ 107. $An object is located at beneath the surfaceof the water. If the fractional compression is , the ratio of hydraulic stress to the corresponding hydraulic strain will be [Given: density of water is and$ (1) $1.96 \times 10^{7} N m^{- 2}$ (2) $1.44 \times 10^{7} Nm^{- 2}$ (3) $2.26 \times 10^{9} Nm^{- 2}$ (4) $1.44 \times 10^{9} Nm^{- 2}$ 108. $The pressure acting on a submarine is 3 \times 10^{5} Pa at a certain depth. If the depth is doubled, the percentageincrease in the pressure acting on the submarine would be : (Assume that atmospheric pressure is 1 \times 10^{5} Pa density of water is (10^{3} kg m^{- 3}, g = 10 ms^{- 2})$ (1) $\frac{200}{3} %$ (2) $\frac{200}{5} %$ (3) $\frac{5}{200} %$ (4) $\frac{3}{200} %$ 109. $The stopping potential in the context of photoelectric effect depends on the following property of incident electromagnetic radiation:$ (1) $Phase$ (2) $Intensity$ (3) $Amplitude$ (4) $Frequency$ 110. $An iron rod of susceptibility 599 is subjected to a magnetizing field of 1200 Am^{- 1} . The permeability of the material of the rod is (Take, μ_{0} = 4 π \times 10^{- 7} T m A^{- 1}) [NEET 2020]$ (1) $8.0 \times 10^{- 5} T m A^{- 1}$ (2) $24 π \times 10^{- 5} T m A^{- 1}$ (3) $2.4 π \times 10^{- 7} T m A^{- 1}$ (4) $2.4 π \times 10^{- 4} T m A^{- 1}$ 111. $A bar magnet of magnetic moment M is cut into two parts of equal length. The magnetic moment of each part will be$ (1) $M$ (2) $2 M$ (3) $zero$ (4) $0. 5 M$ 112. $The magnetic moment of a bar magnet is 0.5 Am^{2} . It is suspended in a uniform magnetic field of 8 \times 10^{- 2} T . The work done in rotating it from its most stable to most unstable position is:$ (1) $8 \times 10^{- 2} J$ (2) $4 \times 10^{- 2} J$ (3) $Zero$ (4) $16 \times 10^{- 2} J$ 113. $The axial field (B_{A}) and the equatorial field (B_{E}) due to a short bar magnet at equal distances are related as$ (1) $B_{A} = 2 B_{E}$ (2) $B_{A} = - 2 B_{E}$ (3) $B_{A} = - B_{E}$ (4) $B_{A} = - 2 π B_{E}$ 114. $The magnitude of axial field due to a bar magnet at a distance of 1 m, is found to be 5 \times 10^{- 8} T . The magnetic moment of the bar magnet is (μ_{0} = 4 π \times 10^{- 7})$ (1) $0.20 Am^{2}$ (2) $0.25 Am^{2}$ (3) $0.50 Am^{2}$ (4) $0.40 Am^{2}$ 115. $A steel wire having a radius of 2.0 mm, carrying a load of 4 kg, is hanging from a ceiling. Given that g = 3.1 π ms^{- 2}, what will be the tensile stress that would be developed in the wire?$ (1) $6.2 \times 10^{6} Nm^{- 2}$ (2) $5.2 \times 10^{6} Nm^{- 2}$ (3) $3.1 \times 10^{6} Nm^{- 2}$ (4) $4.8 \times 10^{6} Nm^{- 2}$ 116. $A bar magnet has length 3 cm, cross-sectional area 2 cm^{2} and magnetic moment 3 Am^{2} . The intensity of magnetisation of bar magnet is$ (1) $2 \times 10^{5} A / m$ (2) $4 \times 10^{5} A / m$ (3) $3 \times 10^{5} A / m$ (4) $5 \times 10^{5} A / m$ 117. $A solenoid has a core of a material with relative permeability 501. The windings of the solenoid are insulated from the core and carry a current of 2.5 A. If the number of turns are 900 per meter. The magnetisation (in A / m) is$ (1) $1.12 \times 10^{6}$ (2) $2.8 \times 10^{6}$ (3) $2.25 \times 10^{6}$ (4) $1.69 \times 10^{6}$ 118. $Magnetic materials used for making permanent magnets (P) and magnets in a transformer (T) have different properties of the following, which property best matches for the type of magnet required?$ (1) $T : Large retentivity, small coercivity$ (2) $P : Large retentivity, large coercivity$ (3) $P : Small retentivity, large coercivity$ (4) $T : Large retentivity, large coercivity$ 119. $In a coil of resistance 8 Ω, the magnetic flux due to an external magnetic field varies with time as φ = \frac{2}{3} (9 - t^{2}) . The value of total heat produced in the coil, till the flux becomes zero, will be _____ J.$ 120. $The value of aluminium susceptibility is 2.2 \times 1 0^{- 5} . The percentage increase in the magnetic field if space within a current carrying toroid is filled with aluminium is \frac{x}{1 0 ^{4}} . Then the value of x is$