JEE Questions for Physics Wave Optics Quiz 9 - MCQExams.com

According to Maxweell\'s hypothesis, a changing electric field given rise to
  • An e.m.f.
  • Electric current
  • Magnetic field
  • Pressure radiant
In an electromagnetic wave, the electric and magnetizing fields are 100 Vm–1 and 0.265 Am–1. The maximum energy flow is
  • 26.5 W/m2
  • 36.5 W/m2
  • 46.7 W/m2
  • None of these
The 21 cm radio wave emitted by hydrogen in interstellar space in due to the interaction called the hyperfine interaction is atomic hydrogen. The energy of the emitted wave is nearly
  • 10–17 Joule
  • 1 Joule
  • 7 × 10–8 Joule
  • 10–24 Joule
TV waves have a wavelength range of 1-10 meter. Their frequency range is MHz is
  • 30-300
  • 3-30
  • 300-3000
  • 3-3000
Maxwell\'s equations describe the fundamental laws of
  • Electricity only
  • Magnetism only
  • Mechanics only
  • Both (a) and (b)
The oscillating electric and magnetic vectors of an electromagnetic wave are oriented along
  • The same direction but differ in phase by 90°
  • The same direction and are in phase
  • Mutually perpendicular directions and are in phase
  • Mutually perpendicular directions and differ in phase by 90°
In which one of the following regions of the electromagnetic spectrum will the vibrational motion of molecules give rise to absorption
  • Ultraviolet
  • Microwaves
  • Infrared
  • Radio waves
An electromagnetic wave travels along z-axis. Which of the following pairs of space and time varying fields would generate such a wave?
  • Ex, By
  • Ey, Bx
  • Ez, Bx
  • Ey, Bz
Maxwell in his famous equation of electromagnetism introduced the concept of
  • a.c. current
  • d.c. current
  • Displacement current
  • Impedance
A signal emitted by an antenna from a certain point can be received at another point of the surface in the form of
  • Sky wave
  • Ground wave
  • Sea wave
  • Both (a) and (b)
Approximate height of ozone layer above the ground is
  • 60 to 70 km
  • 59 km to 80 km
  • 70 km to 100 km
  • 100 km to 200 km
The electromagnetic waves do not transport
  • Energy
  • Charge
  • Momentum
  • Information
An electromagnetic wave, going through vacuum is described by E = E0 sin (kx – ωt); Which of the following is independent of wavelength?
  • k
  • ω
  • k/ω
  • kω
An electromagnetic wave, going through vacuum is described by E = E0 sin (kx – ωt); B = B0 sin(kx – ωt). Which of the following equations is true?
  • E0k = B0ω
  • E0ω = B0k
  • E0 B0 = ωk
  • None of these
A plane electromagnetic wave travels in free space along x–axis. At a particular point in space, the electric field along y-axis is 9.3 Vm–1. The magnetic induction (B) along z-axis is
  • 3.1 × 10–8 T
  • 3 × 10–8 T
  • 3 × 10–6 T
  • 9.3 × 10–6 T
A radio receiver antenna that is 2 m long is oriented along the direction of the electromagnetic wave and receives a signal of intensity 5 × 10–16 W/m2. The maximum instantaneous potential difference across the two ends of the antenna is
  • 1.23 µV
  • 1.23 mV
  • 1.23 V
  • 12.3 mV
A point source of electromagnetic radiation has an average power output of 1500 W. The maximum value of electric field at a distance of 3m from this source in Vm–1 is
  • 500
  • 100

  • Physics-Wave Optics-95677.png

  • Physics-Wave Optics-95678.png
An electromagnetic wave of frequency v = 3.0 MHz passes from vacuum into a dielectric medium with relative permittivity εr = 4.0. Then
  • Wavelength is doubled and the frequency remains unchanged
  • Wavelength is doubled and frequency becomes half
  • Wavelength is halved and frequency remains unchanged
  • Wavelength and frequency both remain unchanged
The region of the atmosphere above troposphere is known as
  • Lithosphere
  • Uppersphere
  • Ionosphere
  • Stratosphere
Which of the following electromagnetic waves have minimum frequency?
  • Microwaves
  • Audible waves
  • Ultrasonic waves
  • Radiowaves
Which one of the following have minimum wavelength?
  • Ultraviolet rays
  • Cosmic rays
  • X-rays
  • y-rays
Radiations of intensity 0.5 W/m2 are striking a metal plate. The pressure on the plate is
  • 0.166 × 10–8 N / m2
  • 0.332 × 10–8 N / m2
  • 0.111 × 10–8 N / m2
  • 0.083 × 10–8 N / m2
Electromagnetic waves travel in a medium which has relative permeability 1.3 and relative permittivity 2.14. Then the speed of the electromagnetic wave in the medium will be
  • 13.6 × 106 m/s
  • 1.8 × 102 m/s
  • 3.6 × 108 m/s
  • 1.8 × 108 m/s

Physics-Wave Optics-95682.png
  • 18 mm
  • 12 mm
  • 6 mm
  • 9 mm
Infrared radiation was discovered in 1800 by
  • William Wollaston
  • William Herschel
  • Wilhelm Roentgen
  • Thomas Young
Which of the following is electromagnetic wave?
  • X-rays and light waves
  • Cosmic rays and sound waves
  • Beta rays and sound waves
  • Alpha rays and sound waves

Physics-Wave Optics-95684.png
  • y-axis
  • x-axis
  • +z-axis
  • –z axis
If c is the speed of electromagnetic waves in vacuum, its speed in a medium of dielectric constant K and relative permeability µr is

  • Physics-Wave Optics-95686.png
  • 2)
    Physics-Wave Optics-95687.png

  • Physics-Wave Optics-95688.png

  • Physics-Wave Optics-95689.png
The rms value of the electric field of the light coming from the Sun is 720 N/C. The average total energy density of the electromagnetic wave is
  • 6.37 × 10–9J/m3
  • 81.35 × 10–12J/m3
  • 3.3 × 10–3J/m3
  • 4.58 × 10–6J/m3
A new system of units is evolved in which the values of µ0 and ϵ0 are 2 and 8 respectively. Then the speed of light in this system will be
  • 0.25
  • 0.5
  • 0.75
  • 1
The magnetic field amplitude of an electromagnetic wave is 2 × 10–7 T. It\'s electric field amplitude if the wave is travelling in free space is
  • 6 Vm–1
  • 60 Vm–1
  • 10/6 Vm–1
  • None of these
Electromagnetic waves can be deflected by
  • Electric field only
  • Magnetic field only
  • Both (a) and (b)
  • None of these
The dielectric constant of air is 1.006. The speed of electromagnetic wave travelling in air a × 108ms–1, where a is about
  • 3
  • 3.88
  • 2.5
  • 3.2
The wavelength of the matter waves is independent of
  • Charge
  • Momentum
  • Velocity
  • Mass
All components of the electromagnetic spectrum in vacuum have the same
  • Energy
  • Velocity
  • Wavelength
  • Frequency
The electromagnetic theory of light failed to explain
  • Photoelectric effect
  • Polarisation
  • Diffraction
  • Interference
An electromagnetic wave propagating along north has its electric field vector upwards. Its magnetic field vector point towards
  • North
  • East
  • West
  • Downwards
Pick out the correct statement in the propagation of electromagnetic waves for communication purposes
  • Space wave propagation is achieved by ionospheric reflection
  • Sky wave propagation is used for line-of-sight communication
  • Electromagnetic waves of frequencies higher than 30 MHz penetrate ionosphere
  • Satellite communication uses sky wave mode of propagation 252
Consider the following statements about electromagnetic waves and choose the correct ones
S1 : Electromagnetic waves having wavelengths 1000 times smaller than light waves are called X-rays.
S2 : Ultraviolet waves are used in the treatment of swollen joints.
S3 : Alpha and gamma rays are not electromagnetic waves.
S4: de-Broglie waves are not electromagnetic in nature.
S5 : Electromagnetic waves exhibit polarization while sound waves do not
  • S1, S4 and S5
  • S3, S4 and S5
  • S1, S3 and S5
  • S2, S3 and S4
The electric and the magnetic field, associated with and e.m. wave propagating along the +z - axis, can be represented by

  • Physics-Wave Optics-95700.png
  • 2)
    Physics-Wave Optics-95701.png

  • Physics-Wave Optics-95702.png

  • Physics-Wave Optics-95703.png
Which one of the following is INCORRECT statement in the transmission of electromagnetic waves
  • Ground wave propagation is for high frequency transmission
  • Sky wave propagation is facilitated by ionospheric layers
  • Space wave of high frequency and is suitable for line of sight communication
  • Space wave is used for satellite communication
  • Very high frequency waves cannot be reflected by the ionospheric layers
The electric field of a plane electromagnetic wave varies with time of amplitude 2 Vm–1 propagating along z-axis. The average energy density of the magnetic field is (in Jm–3)
  • 13.29 × 10–12
  • 8.86 × 10–12
  • 17.72 × 10–12
  • 4.43 × 10–12

Physics-Wave Optics-95706.png

  • Physics-Wave Optics-95707.png
  • 2)
    Physics-Wave Optics-95708.png

  • Physics-Wave Optics-95709.png

  • Physics-Wave Optics-95710.png
A ray of light of intensity I is incident on a parallel glass-slab at a point A as shown in fig. It undergoes partial reflection and refraction. At each reflection 25% of incident energy is reflected. The rays AB and A\' B\' undergo interference. The ratio Imax / Imin is
Physics-Wave Optics-95712.png
  • 4 : 1
  • 8 : 1
  • 7 : 1
  • 49 : 1
A thin slice is cut out of a glass cylinder along a plane parallel to its axis. The slice is placed on a flat glass plate as shown. The observed interference fringes from this combination shall be
Physics-Wave Optics-95714.png
  • Straight
  • Circular
  • Equally spaced
  • Having fringe which increases as we go outwards
In the adjacent diagram, CP represents a wavefront and AO & BP, corresponding two rays. Find the condition on θ for constructive interference at P between the ray BP and reflected ray OP
Physics-Wave Optics-95715.png
  • cos θ = 3λ/2d
  • cos θ = λ/4d
  • sec θ – cos θ = λ/d
  • sec θ – cos θ = 4λ/d
In Young\'s double slit experiment, if the two slits are illuminated with separate sources, no interference pattern is observed because
  • There will be no constant phase difference between the two waves
  • The wavelengths are not equal
  • The amplitudes are not equal
  • None of the above
Air has refractive index 1.0003. The thickness of air column, which will. have one more wavelength of yellow light (6000 Å) than in the same thickness of vacuum is
  • 2 mm
  • 2 cm
  • 2 m
  • 2 km
A beam of electron is used in an YDSE experiment. The slit width is d. When the velocity of electron is increased, then
  • No interference is observed
  • Fringe width increases
  • Fringe width decreases
  • Fringe width remains same
In Young\'s double slit experiment intensity at a point is (1/of the maximum intensity. Angular position of this point is
  • sin–1(λ/d)
  • sin–1 (λ/2d)
  • sin–1 (λ/3 d)
  • sin–1 (λ/4d)
0:0:1


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