Electromagnetic Waves PYQs Set 4 (PDF)

Set 4 of 9 · Questions 91-120 of 244

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Mere Teacher · Previous Year Questions NEET Physics · Electromagnetic Waves · Set 4 (Q91-120)
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91. $An electromagnetic wave of frequency 3.0 MHz passes from vacuum into a non-magnetic medium with permittivity, ϵ = 16 ϵ_{0} . Where ϵ_{0} is the free space permittivity. The change in wavelength is$ (1) $- 75 m$ (2) $+ 75 m$ (3) $- 50 m$ (4) $+ 50 m$ 92. $A plane electromagnetic wave of frequency 50 MHz travels in free space. If the average energy densities in the electric field and magnetic field are K_{E} and K_{B} respectively, then the correct option in the following is$ (1) $K_{E} = K_{B}$ (2) $K_{E} = K_{B} = 0$ (3) $K_{E} > K_{B}$ (4) $K_{E} < K_{B}$ 93. $Electromagnetic radiation of intensity 0.6 Wm^{- 2} is falling on a black surface. The radiation pressure on the surface is$ (1) $2 \times 10^{- 9} Nm^{- 2}$ (2) $3 \times 10^{- 9} Nm^{- 2}$ (3) $4 \times 10^{- 9} Nm^{- 2}$ (4) $6 \times 10^{- 9} Nm^{- 2}$ 94. $Which of the following statement does not hold good for thermal radiation?$ (1) $The wavelength changes when it travels from one medium to another.$ (2) $The frequency changes when it travels from one medium to another.$ (3) $The speed changes when it travels from one medium to another.$ (4) $They travel in straight line in a given medium.$ 95. $If a source is transmitting electromagnetic wave of frequency 8.2 \times 10^{6} Hz, then wavelength of the electromagnetic waves transmitted from the source will be$ (1) $36.5 m$ (2) $40.5 m$ (3) $42.3 m$ (4) $50.9 m$ 96. $For a transparent medium relative permeability and permittivity, μ_{r} and ϵ_{r} are 1.0 and 1.44 respectively. The velocity of light in this medium would be$ (1) $2.5 \times 1 0^{8} m / s$ (2) $3 \times 1 0^{8} m / s$ (3) $2.08 \times 1 0^{8} m / s$ (4) $4.32 \times 1 0^{8} m / s$ 97. $The waves emitted when a metal target is bombarded with high energy electrons are$ (1) $Microwaves$ (2) $Infrared rays$ (3) $X-rays$ (4) $Radio Waves$ 98. $The electric field in an electromagnetic wave is given by E = i 40 cos ω (t - z / c) NC^{- 1} . The magnetic field induction of this wave is (in SI unit) :$ (1) $B = k \frac{40}{C} cos ω (t - z / c)$ (2) $B = j 40 cos ω (t - z / c)$ (3) $B = i \frac{40}{C} cos ω (t - z / c)$ (4) $B = j \frac{40}{C} cos ω (t - z / c)$ 99. $Light with an energy flux of 25 \times 1 0^{4} W m^{- 2} falls on a perfectly reflecting surface at normal incidence. If the surface area is 15 c m^{2}, the average force exerted on the surface is$ (1) $1.25 \times 1 0^{- 6} N$ (2) $2.50 \times 1 0^{- 6} N$ (3) $1.20 \times 1 0^{- 6} N$ (4) $3.0 \times 1 0^{- 6} N$ 100. $The electric field of a plane electromagnetic wave is given by E = E_{0} i cos (kz) cos (ωt) The corresponding magnetic field B \to is then given by:$ (1) $B = \frac{E _{0}}{C} j sin (kz) sin (ωt)$ (2) $B = \frac{E _{0}}{C} j sin (kz) cos (ωt)$ (3) $B = \frac{E _{0}}{C} j cos (kz) sin (ωt)$ (4) $B = \frac{E _{0}}{C} k sin (kz) cos (ωt)$ 101. $For a transparent medium relative permeability and permittivity, μ_{r} and ϵ_{r}, are 1.0 and 1.44 respectively. The velocity of light in this medium would be [NEET 2019]$ (1) $2.5 \times 10^{8} m / s$ (2) $3 \times 10^{8} m / s$ (3) $2.08 \times 10^{8} m / s$ (4) $4.32 \times 10^{8} m / s$ 102. $An electromagnetic wave has its electric and magnetic fields given by E (t) = E_{m} sin (kx - ω t) B (t) = B_{m} sin (kx - ω t) If the direction of E_{m} & B_{m} are in the direction of ı + j and ı - j respectively, the unit vector that gives the direction of propagation of the wave is$ (1) $- k$ (2) $k$ (3) $ı$ (4) $- ı$ 103. $The magnetic field in a plane electromagnetic wave is given by B_{y} = 2 \times 10^{- 7} sin (π \times 10^{3} x + 3 π \times 10^{11} t) T Calculate the wavelength. [NEET 2020]$ (1) $π \times 10^{3} m$ (2) $2 \times 10^{- 3} m$ (3) $2 \times 10^{3} m$ (4) $π \times 10^{- 3} m$ 104. $An electromagnetic wave of frequency 1 \times 10^{14} Hz is propagating along z -axis. The amplitude of electric field is 4 Vm^{- 1}, then energy density of the electric field will be (Permittivity of free space = 8.8 \times 10^{- 12} C^{2} N^{- 1} m^{- 2})$ (1) $35.2 \times 10^{- 13} Jm^{- 3}$ (2) $70.4 \times 10^{- 13} Jm^{- 3}$ (3) $70.4 \times 10^{- 12} Jm^{- 3}$ (4) $35.2 \times 10^{- 12} Jm^{- 3}$ 105. $The property which is not of an electromagnetic wave travelling in free space is that [NEET 2024]$ (1) $They are transverse in nature$ (2) $The energy density in electric field is equal to energy density in magnetic field$ (3) $They travel with a speed equal to \frac{1}{μ _{0} ϵ _{0}}$ (4) $They originate from charges moving with uniform speed$ 106. $The displacement current through the plates of a parallel plate capacitor of capacitance 30 μ F is 150 μ A . The capacitor is charged by a source of varying potential at the rate of$ (1) $3.5 Vs^{- 1}$ (2) $2 Vs^{- 1}$ (3) $5 Vs^{- 1}$ (4) $3 Vs^{- 1}$ 107. $A plane electromagnetic wave of frequency 20 MHz travels through a space along x direction. If the electric field vector at a certain point in space is 6 V m m^{- 1}, what is the magnetic field vector at that point?$ (1) $2 T$ (2) $2 \times 10^{- 8} T$ (3) $1 2 T$ (4) $12\times 1 0^{- 8}$ 108. $The frequency order for X ‐rays (A), γ ‐rays (B), UV rays(c) is$ (1) $B > A > C$ (2) $A > B > C$ (3) $C > B > A$ (4) $A > C > B .$ 109. $A plane electromagnetic wave of frequency 20 MHz travels in free space along the + x direction. At a particular point in space and time, the electric field vector of the wave is E_{y} = 9.3 Vm^{- 1} . Then, the magnetic field vector of the wave at that point is$ (1) $B_{z} = 6.2 \times 10^{- 8} T$ (2) $B_{z} = 3.1 \times 10^{- 8} T$ (3) $B_{z} = 1.55 \times 10^{- 8} T$ (4) $B_{z} = 9.3 \times 10^{- 8} T$ 110. $Which of the following radiations deflected by electric field?$ (1) $γ -rays$ (2) $X-rays$ (3) $α -particles$ (4) $neutrons$ 111. $In a plane electromagnetic wave travelling in free space, the electric field component oscillates sinusoidally at a frequency of 2.0 \times 10^{10} Hz and amplitude 48 Vm^{- 1} . Then, the amplitude of oscillating magnetic field is (Speed of light in free space = 3 \times 10^{8} ms^{- 1}) [NEET 2023]$ (1) $1.6 \times 10^{- 8} T$ (2) $1.6 \times 10^{- 7} T$ (3) $1.6 \times 10^{- 6} T$ (4) $1.6 \times 10^{- 9} T$ 112. $A light beam of intensity 20 W cm^{- 2} is incident normally on a perfectly reflecting surface of sides 25 cm \times 15 cm . The momentum imparted to the surface by the light per second is$ (1) $5 \times 10^{- 5} kg m s^{- 1}$ (2) $1.2\times 1 0^{- 5} kg m s-1$ (3) $2 \times 10^{- 5} kg m s^{- 1}$ (4) $1 \times 10^{- 5} kg m s^{- 1}$ 113. $Match Column-I with Column-II Column-I (Electromagnetic waves) A. AM radio waves B. Microwaves C. Infrared radiations D. X-rays Column-II (Wavelength) I. 10^{- 10} m II. 10^{2} m III. 10^{- 2} m IV. 10^{- 4} m Choose the correct answer from the options given below. [NEET 2022]$ (1) $A-IV, B-III, C-II, D-I$ (2) $A-III, B-II, C-I, D-IV$ (3) $A-III, B-IV, C-II, D-I$ (4) $A-II, B-III, C-IV, D-I$ 114. $All components of the electromagnetic spectrum in vacuum have the same$ (1) $energy$ (2) $velocity$ (3) $wavelength$ (4) $frequency.$ 115. $An EM wave propagating in x-direction has a wavelength of 8 mm. The electric field vibrating y-direction has maximum magnitude of 60 V m^{- 1} . Choose the correct equations for electric and magnetic fields if the EM wave is propagating in vacuum:$ (1) $E_{y} = 60 sin [\frac{π}{4} \times 1 0^{3} (x - 3 \times 1 0^{8} t)] j V m^{- 1}; B_{z} = 2 sin [\frac{π}{4} \times 1 0^{3} (x - 3 \times 1 0^{8} t)] k T$ (2) $E_{y} = 60 sin [\frac{π}{4} \times 1 0^{3} (x - 3 \times 1 0^{8} t)] j V m^{- 1}; B_{z} = 2 \times 1 0^{- 7} sin [\frac{π}{4} \times 1 0^{3} (x - 3 \times 1 0^{8} t)] k T$ (3) $E_{y} = 2 \times 1 0^{- 7} sin [\frac{π}{4} \times 1 0^{3} (x - 3 \times 1 0^{8} t)] j V m^{- 1}; B_{z} = 60 sin [\frac{π}{4} \times 1 0^{3} (x - 3 \times 1 0^{8} t)] k T$ (4) $E_{y} = 2 \times 1 0^{- 7} sin [\frac{π}{4} \times 1 0^{4} (x - 4 \times 1 0^{8} t)] j V m^{- 1}; B_{z} = 60 sin [\frac{π}{4} \times 1 0^{4} (x - 4 \times 1 0^{8} t)] k T$ 116. $If electric field intensity of a uniform plane electromagnetic wave is given as E = -301.6 sin(kz - ωt) a_{x} + 452.4 sin(kz - ωt) a_{y} v / m Then, magnetic intensity H of this wave in A m^{- 1} will be: [Given: Speed of light in vacuum c = 3 x 10 m s^{- 1}, permeability of vacuum μ_{0} = 4 π \times 1 0^{- 7} N A^{- 2}]$ (1) $+ 0.8 sin (kz - ωt) a_{y} + 0.8 sin (kz - ωt) a_{x}$ (2) $+1.0\times 1 0^{- 6} sinkz-ωtay+1.5\times 1 0^{- 6} kz-ωtax$ (3) $- 0.8 sin (kz - ωt) a_{y} - 1.2 sin (kz - ωt) a_{x}$ (4) $-0.1\times 1 0^{- 6} sinkz-ωtay-1.5\times 1 0^{- 6} sinkz-ωtax$ 117. $A plane electromagnetic wave travels in free space along the x -direction. The electric field component of the wave at a particular point of space and time is E = 6 Vm^{- 1} along y -direction. Its corresponding magnetic field component, B would be:$ (1) $2\times 1 0^{- 8} T along z -direction$ (2) $6\times 1 0^{- 8} T along x -direction$ (3) $6\times 1 0^{- 8} T along z -direction$ (4) $2\times 1 0^{- 8} T along y -direction$ 118. $The electromagnetic waves travel in a medium at a speed of 2.0 x 1 0^{8} m/s. The relative permeability of the medium is 1.0. The relative permittivity of the medium will be:$ (1) $2.25$ (2) $4.25$ (3) $6.25$ (4) $8.25$ 119. $The frequency of electromagnetic wave, which best suited to observe a particle of radius 3 \times 1 0^{- 4} cm is of the order of$ (1) $1 0^{15}$ (2) $1 0^{14}$ (3) $1 0^{13}$ (4) $1 0^{12}$ 120. $For Young's double slit experiment, two statements are given below [NEET 2023] Statement I: If screen is moved away from the plane of slits, angular separation of the fringes remains constant. Statement II: If the monochromatic source is replaced by another monochromatic source of larger wavelength. the angular separation of fringes decreases. In the light of the above statements, choose the correct answer from the options given below$ (1) $Both Statement I and Statement II are incorrect.$ (2) $Statement I is correct but Statement II is incorrect.$ (3) $Statement I is incorrect but Statement II is correct.$ (4) $Both Statement I and Statement II are correct.$