430+ Broadband Communication Systems Solved MCQs

These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Electronics and Telecommunication Engineering [ENTC] .

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1.	Who proposed the idea of transmission of light via dielectric waveguide structure?
A.	christian huygens
B.	karpon and bockham
C.	hondros and debye
D.	albert einstein
Answer» C. hondros and debye

discuss

2.	Who proposed the use of clad waveguide structure?
A.	edward appleton
B.	schriever
C.	kao and hockham
D.	james maxwell
Answer» C. kao and hockham

discuss

3.	Which law gives the relationship between refractive index of the dielectric?
A.	law of reflection
B.	law of refraction (snell’s law).
C.	millman’s law
D.	huygen’s law
Answer» B. law of refraction (snell’s law).

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4.	The light sources used in fibre optics communication are :
A.	led’s and lasers
B.	phototransistors
C.	xenon lights
D.	incandescent
Answer» A. led’s and lasers

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5.	The ________ ray passes through the axis of the fiber core.
A.	reflected
B.	refracted
C.	meridional
D.	shew
Answer» C. meridional

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6.	Light incident on fibers of angles________the acceptance angle do not propagate into the fiber
A.	less than
B.	greater than
C.	equal to
D.	less than and equal to
Answer» B. greater than

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7.	What is the numerical aperture of the fiber if the angle of acceptance is 16 degree
A.	0.50
B.	0.36
C.	0.20
D.	0.27
Answer» D. 0.27

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8.	The ratio of speed of light in air to the speed of light in another medium is called as_________
A.	speed factor
B.	dielectric constant
C.	reflection index
D.	refraction index
Answer» D. refraction index

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9.	When a ray of light enters one medium from another medium, which quality will not change
A.	direction
B.	frequency
C.	speed
D.	wavelength
Answer» B. frequency

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10.	An optical fiber has core-index of 1.480 and a cladding index of 1.478. What should be the core size for single mode operation at 1310nm?
A.	7.31μm
B.	8.71μm
C.	5.26μm
D.	6.50μm
Answer» D. 6.50μm

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11.	An optical fiber has a core radius 2μmand a numerical aperture of 0.1. Will this fiber operate at single mode at 600 nm?
A.	yes
B.	no
Answer» A. yes

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12.	What is needed to predict the performance characteristicsics of single mode fibers?
A.	the intermodal delay effect
B.	geometric distribution of light in a propagating mode
C.	fractional power flow in the cladding of fiber
D.	normalized frequency
Answer» B. geometric distribution of light in a propagating mode

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13.	Which equation is used to calculate MFD?
A.	maxwell’s equations
B.	peterman equations
C.	allen cahn equations
D.	boltzmann’s equations
Answer» B. peterman equations

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14.	A single mode fiber has mode field diameter 10.2μmand V=2.20. What is the core diameter of this fiber?
A.	11.1μm
B.	13.2μm
C.	7.6μm
D.	10.1μm
Answer» D. 10.1μm

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15.	The difference between the modes’ refractive indices is called as
A.	polarization
B.	cutoff
C.	fiber birefringence
D.	fiber splicing
Answer» C. fiber birefringence

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16.	A single mode fiber has a beat length of 4cm at 1200nm. What is birefringence?
A.	2*10-5
B.	1.2*10-5
C.	3*10-5
D.	2
Answer» C. 3*10-5

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17.	How many propagation modes are present in single mode fibers?
A.	one
B.	two
C.	three
D.	five
Answer» B. two

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18.	Numerical aperture is constant in case of step index fiber. State whether the statement is true or false.
A.	true
B.	false
Answer» A. true

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19.	Plastic fibers are less widely used than glass fibers. State whether the statement is true or false.
A.	true
B.	false
Answer» A. true

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20.	Which equations are best suited for the study of electromagnetic wave propagation?
A.	maxwell’s equations
B.	allen-cahn equations
C.	avrami equations
D.	boltzmann’s equations
Answer» A. maxwell’s equations

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21.	When λ is optical wavelength in vacuum, k is given by k=2Π/λ. What does k stand for in the above equation?
A.	phase propagation constant
B.	dielectric constant
C.	boltzmann’s constant
D.	free-space constant
Answer» A. phase propagation constant

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22.	Constructive interference occurs when total phase change after two successive reflections at upper and lower interfaces is equal to? (Where m is integer)
A.	2Πm
B.	Πm
C.	Πm/4
D.	Πm/6
Answer» A. 2Πm

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23.	. When light is described as an electromagnetic wave, it consists of a periodically varying electric E and magnetic field H which are oriented at an angle
A.	90 degree to each other
B.	less than 90 degree
C.	greater than 90 degree
D.	180 degree apart
Answer» A. 90 degree to each other

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24.	A monochromatic wave propagates along a waveguide in z direction. These points of constant phase travel in constant phase travel at a phase velocity Vp is given by
A.	vp=ω/β
B.	vp=ω/c
C.	vp=c/n
D.	vp=mass/acceleration
Answer» A. vp=ω/β

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25.	A most important velocity in the study of transmission characteristics of optical fiber is
A.	phase velocity
B.	group velocity
C.	normalized velocity
D.	average velocity
Answer» B. group velocity

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26.	Refraction is the
A.	bending of light waves
B.	reflection of light waves
C.	diffusion of light waves
D.	refraction of light waves
Answer» A. bending of light waves

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27.	The phenomenon which occurs when an incident wave strikes an interface at an angle greater than the critical angle with respect to the normal to the surface is called as
A.	refraction
B.	partial internal reflection
C.	total internal reflection
D.	limiting case of refraction
Answer» C. total internal reflection

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28.	Photonic crystal fibers also called as
A.	conventional fibers
B.	dotted fibers
C.	stripped fibers
D.	holey fibers
Answer» D. holey fibers

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29.	Conventional optical fibers has more transmission losses than photonic crystal fibers. State whether the statement is true or false.
A.	true
B.	false
Answer» A. true

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30.	Losses in photonic crystal fibers are reduced to a level of
A.	0.1db/km
B.	0.2db/km
C.	0.3db/km
D.	0.4db/km
Answer» C. 0.3db/km

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31.	The high index contrast enables the PCF core to be reduced from around 8 μmin conventional fiber to
A.	less than 1μm
B.	more than 5μm
C.	more than 3μm
D.	more than 2μm
Answer» A. less than 1μm

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32.	The periodic arrangement of cladding air holes in photonic band gap fibers provides for the formation of a photonic band gap in the
A.	h-plane of fiber
B.	e-plane of fiber
C.	e-h-plane of fiber
D.	transverse plane of fiber
Answer» D. transverse plane of fiber

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33.	In index-guided photonic crystal fiber structure, the dark areas are air holes. What does white areas suggests?
A.	air
B.	silica
C.	water
D.	plasma
Answer» D. plasma

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34.	The unit of measurement of attenuation in optical fibers is
A.	km
B.	db
C.	db/km
D.	coulomb’s
Answer» C. db/km

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35.	The optical fiber incurs a loss in signal power as light travels down the fiber which is called as
A.	scattering
B.	attenuation
C.	absorption
D.	refraction
Answer» B. attenuation

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36.	If the input power 100μW is launched into 6 km of fiber, the mean optical power at the fiber output is 2μW. What is the overall signal attenuation through the fiber assuming there are no connectors or splices?
A.	15.23db
B.	16.98db
C.	17.12db
D.	16.62db
Answer» B. 16.98db

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37.	A device which reduces the intensity of light in optical fiber communications is
A.	compressor
B.	optical attenuator
C.	barometer
D.	reducer
Answer» B. optical attenuator

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38.	. A decibel may be defined as the ratio of input and output optical power for a particular optical wavelength. State whether the following statement is true or false.
A.	true
B.	false
Answer» A. true

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39.	. When the input and output power in an optical fiber is 120μW & 3μW respectively and the length of the fiber is 8 km. What is the signal attenuation per km for the fiber?
A.	3db/km
B.	2db/km
C.	1db/km
D.	4db/km
Answer» B. 2db/km

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40.	A multimode step index fiber has a normalized frequency of 72. Estimate the number of guided modes.
A.	2846
B.	2592
C.	2432
D.	2136
Answer» B. 2592

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41.	A graded-index fiber has a core with parabolic refractive index profile of diameter of 30μm, NA=0.2, λ=1μm. Estimate the normalised frequency.
A.	19.32
B.	18.84
C.	16.28
D.	17.12
Answer» B. 18.84

discuss

42.	A step-index fiber has core refractive index 1.46 and radius 4.5μm. Find the cutoff wavelength to exhibit single mode operation. Use relative index difference as 0.25%.
A.	1.326μm
B.	0.124μm
C.	1.214μm
D.	0.123μm
Answer» C. 1.214μm

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43.	One of the given statements is true for intermodal dispersion. Choose the right one.
A.	low in single mode and considerable in multimode fiber
B.	low in both single mode and multimode fiber
C.	high in both single mode and multimode fiber
D.	high in single mode and low in multimode fiber
Answer» A. low in single mode and considerable in multimode fiber

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44.	For lower bandwidth applications,
A.	single mode fiber is advantageous
B.	photonic crystal fibers are advantageous
C.	coaxial cables are advantageous
D.	multimode fiber is advantageous
Answer» D. multimode fiber is advantageous

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45.	Most of the optical power is carried out in core region than in cladding. State true or false:
A.	true
B.	false
Answer» A. true

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46.	Meridional rays in graded index fibers follow
A.	straight path along the axis
B.	curved path along the axis
C.	path where rays changes angles at core-cladding interface
D.	helical path
Answer» B. curved path along the axis

discuss

47.	What is the unit of normalized frequency?
A.	hertz
B.	meter/sec
C.	coulombs
D.	it is a dimensionless quantity
Answer» D. it is a dimensionless quantity

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48.	. Skew rays follow a
A.	hyperbolic path along the axis
B.	parabolic path along the axis
C.	helical path
D.	path where rays changes angles at core-cladding interface
Answer» C. helical path

discuss

49.	A graded-index fiber has a core with parabolic refractive index profile of diameter of 30μm, NA=0.2, λ=1μm. Estimate the normalised frequency.
A.	19.32
B.	18.84
C.	16.28
D.	17.12
Answer» B. 18.84

discuss

50.	A step-index fiber has core refractive index 1.46 and radius 4.5μm. Find the cutoff wavelength to exhibit single mode operation. Use relative index difference as 0.25%.
A.	1.326μm
B.	0.124μm
C.	1.214μm
D.	0.123μm
Answer» C. 1.214μm

discuss

430+ Broadband Communication Systems Solved MCQs

Who proposed the idea of transmission of light via dielectric waveguide structure?

Who proposed the use of clad waveguide structure?

Which law gives the relationship between refractive index of the dielectric?

The light sources used in fibre optics communication are :

The ________ ray passes through the axis of the fiber core.

Light incident on fibers of angles________the acceptance angle do not propagate into the fiber

What is the numerical aperture of the fiber if the angle of acceptance is 16 degree

The ratio of speed of light in air to the speed of light in another medium is called as_________

When a ray of light enters one medium from another medium, which quality will not change

An optical fiber has core-index of 1.480 and a cladding index of 1.478. What should be the core size for single mode operation at 1310nm?

An optical fiber has a core radius 2μmand a numerical aperture of 0.1. Will this fiber operate at single mode at 600 nm?

What is needed to predict the performance characteristicsics of single mode fibers?

Which equation is used to calculate MFD?

A single mode fiber has mode field diameter 10.2μmand V=2.20. What is the core diameter of this fiber?

The difference between the modes’ refractive indices is called as

A single mode fiber has a beat length of 4cm at 1200nm. What is birefringence?

How many propagation modes are present in single mode fibers?

Numerical aperture is constant in case of step index fiber. State whether the statement is true or false.

Plastic fibers are less widely used than glass fibers. State whether the statement is true or false.

Which equations are best suited for the study of electromagnetic wave propagation?

When λ is optical wavelength in vacuum, k is given by k=2Π/λ. What does k stand for in the above equation?

Constructive interference occurs when total phase change after two successive reflections at upper and lower interfaces is equal to? (Where m is integer)

. When light is described as an electromagnetic wave, it consists of a periodically varying electric E and magnetic field H which are oriented at an angle

A monochromatic wave propagates along a waveguide in z direction. These points of constant phase travel in constant phase travel at a phase velocity Vp is given by

A most important velocity in the study of transmission characteristics of optical fiber is

Refraction is the

The phenomenon which occurs when an incident wave strikes an interface at an angle greater than the critical angle with respect to the normal to the surface is called as

Photonic crystal fibers also called as

Conventional optical fibers has more transmission losses than photonic crystal fibers. State whether the statement is true or false.

Losses in photonic crystal fibers are reduced to a level of

The high index contrast enables the PCF core to be reduced from around 8 μmin conventional fiber to

The periodic arrangement of cladding air holes in photonic band gap fibers provides for the formation of a photonic band gap in the

In index-guided photonic crystal fiber structure, the dark areas are air holes. What does white areas suggests?

The unit of measurement of attenuation in optical fibers is

The optical fiber incurs a loss in signal power as light travels down the fiber which is called as

If the input power 100μW is launched into 6 km of fiber, the mean optical power at the fiber output is 2μW. What is the overall signal attenuation through the fiber assuming there are no connectors or splices?

A device which reduces the intensity of light in optical fiber communications is

. A decibel may be defined as the ratio of input and output optical power for a particular optical wavelength. State whether the following statement is true or false.

. When the input and output power in an optical fiber is 120μW & 3μW respectively and the length of the fiber is 8 km. What is the signal attenuation per km for the fiber?

A multimode step index fiber has a normalized frequency of 72. Estimate the number of guided modes.

A graded-index fiber has a core with parabolic refractive index profile of diameter of 30μm, NA=0.2, λ=1μm. Estimate the normalised frequency.

A step-index fiber has core refractive index 1.46 and radius 4.5μm. Find the cutoff wavelength to exhibit single mode operation. Use relative index difference as 0.25%.

One of the given statements is true for intermodal dispersion. Choose the right one.

For lower bandwidth applications,

Most of the optical power is carried out in core region than in cladding. State true or false:

Meridional rays in graded index fibers follow

What is the unit of normalized frequency?

. Skew rays follow a

A graded-index fiber has a core with parabolic refractive index profile of diameter of 30μm, NA=0.2, λ=1μm. Estimate the normalised frequency.

A step-index fiber has core refractive index 1.46 and radius 4.5μm. Find the cutoff wavelength to exhibit single mode operation. Use relative index difference as 0.25%.