Physics MCQs Test 5

Electromagnetic Waves

1. What is the ratio of the speed of infrared and ultraviolet rays in a vacuum?
a) 1:5
b) 2:1
c) 1
d) 0
View Answer

Answer: c
Explanation: Ratio = 1 because the speed of an electromagnetic wave in vacuum is independent of its wavelength or frequency. Therefore, the ratio of speed of infrared and ultraviolet rays in a vacuum is one.

2. What is the velocity of electromagnetic wave in free space?
a) c = √μ0ε0
b) c = 1𝜇0𝜀0√
c) c = 1𝜇0𝜀0
d) c = μ0ε0
View Answer

Answer: b
Explanation: The value of c is the same for all types of electromagnetic waves because the constants μ0 and ε0 do not depend on the frequency or wavelength of the electromagnetic waves. So, the velocity of electromagnetic wave in free space is given as:
c = 1𝜇0𝜀0√.

3. Which basic oscillatory circuit is used these days to produce electromagnetic waves?
a) LC oscillatory circuit
b) LCR circuit
c) Inductive circuit
d) Capacitive circuit
View Answer

Answer: a
Explanation: LC-oscillatory circuit is used these days to produce electromagnetic waves. It generates electromagnetic waves of frequency, v = 12𝜋𝐿𝐶√. Therefore, the basic oscillatory circuit is used these days to produce electromagnetic waves is LC oscillatory circuit.

4. Is the ratio of frequencies of UV rays and IR rays in the glass more than, less than or equal to 1?
a) Insufficient data
b) Equal to 1
c) Less than 1
d) More than 1
View Answer

Answer: d
Explanation: The ratio of frequencies of UV rays and IR rays in the glass is more than 1.This is because the frequency of UV rays is greater than that of infrared rays. This situation is applicable in glass or vacuum or air.

5. For which frequency of light, the human eye is most sensitive?
a) 55.405 × 1014 Hz
b) 95.405 × 1014 Hz
c) 5.405 × 1014 Hz
d) 79.405 × 1014 Hz
View Answer

Answer: c
Explanation: Human eye is sensitive to light of wavelength ➔ λ =5550 angstrom.
So its frequency is v = 𝑐𝜆
v = 3 × 1085550 × 10-10
v = 5.405 × 1014 Hz

6. Microwaves can’t be used for long-distance transmission of signals.

a) True
b) False
View Answer

Answer: b
Explanation: Due to their smaller wavelength, microwaves are not bent by objects of normal dimensions. So they can be used to beam signal in a particular direction. Therefore, microwaves can be used for long-distance transmission of signals.

7. If the wavelength of electromagnetic radiation is doubled, what will happen to the energy of photons?
a) Doubled
b) Halved
c) Remains the same
d) Becomes zero
View Answer

Answer: b
Explanation: Energy of a photon,
E = hv = ℎ𝑐𝜆.
E ∝ 1𝜆.
When the wavelength of electromagnetic radiation is doubled, the energy of the photons is halved.

8. What is the time period of visible light for which human eye is most sensitive?
a) 1.85 × 1015 s
b) 1.85 × 10-15 s
c) 3 × 108s
d) 5 × 1016 s
View Answer

Answer: b
Explanation: T = 1𝑣
T = 𝜆𝑐
T = 5550 × 10−103 × 108
T = 1.85 × 10-15 s.

Ray Optics and Optical Instruments

1. Identify the factor on which the angle of deviation of the prism does not depend.

a) The angle of incidence
b) The material of the prism
c) The angle of reflection
d) The wavelength of light used
View Answer

Answer: c
Explanation: Factors on which the angle of deviation depends are ➔ the angle of incidence, the material of the prism, the wavelength of light used, and the angle of the prism. So, the factor on which the angle of deviation that does not depend on is the angle of reflection.

2. Calculate the refractive index of the material of an equilateral prism for which the angle of minimum deviation is 60°.
a) 3√2
b) √3
c) 12
d) 12√
View Answer

Answer: b
Explanation: Refractive index of the prism material is μ = {𝑠𝑖𝑛(𝐴+𝛿𝑚)2}{𝑠𝑖𝑛𝐴2}
μ = {𝑠𝑖𝑛(60𝑜+60𝑜)2}{𝑠𝑖𝑛60𝑜2}
μ = √3.

3. Which of the following causes dispersion?
a) Refraction
b) Reflection
c) Total internal reflection
d) Total internal dispersion
View Answer

Answer: a
Explanation: The reason is that for a given angle f incidence, the reflection is the same for all the wavelengths of white light while the angle of refraction is different for different wavelengths. Therefore, this is how dispersion is caused.

4. What happens to the frequency and the wavelength when light passes from a rarer to a denser medium?

a) Wavelength remains unchanged but frequency changes
b) They are independent
c) Wavelength and frequency changes
d) Wavelength changes but the frequency remain unchanged
View Answer

Answer: d
Explanation: When light passes from a rarer to a denser medium, the wavelength of light changes but the frequency remains unchanged. Therefore, there is no change in the frequency of light, only the wavelength changes.

5. What is the relative refractive index of water with respect to glass?
a) Unity
b) More than unity
c) Less than unity
d) Zero
View Answer

Answer: c
Explanation: Absolute refractive index = 𝑆𝑝𝑒𝑒𝑑𝑜𝑓𝑙𝑖𝑔ℎ𝑡𝑖𝑛𝑣𝑎𝑐𝑢𝑢𝑚. The relative refractive index of water with respect to glass is less than unity.

6. The refraction in a water tank makes apparent depth the same throughout.

a) True
b) False
View Answer

Answer: b
Explanation: No, this statement is false. Apparent depth is maximum for that part of the bottom of the tank which is observed normally. Apparent depth decreases with increasing obliquity. Therefore, the refraction in a water tank does not make apparent depth the same throughout.

7. What will be the color of the sky in the absence of the atmosphere?
a) White
b) Dark
c) Blue
d) Pink
View Answer

Answer: b
Explanation: The sunlight will not be scattered in the absence of the atmosphere. So the sky will appear dark. So, the sky will no longer be blue in the absence of an atmosphere.

8. On what factor does the normal shift through a refracting medium depend?
a) The thickness of the refracting medium
b) Angle of Prism
c) Angle of deviation
d) Convection
View Answer

Answer: a
Explanation: The normal shift depends on the thickness of the refracting medium and the refractive index of the material. The normal shift does not depend on the angle of the prism, angle of deviation, and convection.

9. A lens immersed in a transparent liquid is not visible. Under what condition can this happen?
a) Less refractive index
b) Higher refractive index
c) Same refractive index
d) Total internal reflection is zero
View Answer

Answer: c
Explanation: When the refractive index of the liquid is the same as the lens material, no light will be reflected by the lens and hence it will not be visible. So, the lens immersed in a transparent liquid will not be visible.

10. What is the cause of the blue color of the ocean?
a) Reflection
b) Scattering of light by water molecules
c) Total internal reflection
d) Refraction
View Answer

Answer: b
Explanation: The blue color of the ocean is due to the preferential scattering of light by water molecules. This is the underlying reason for many other phenomena such as why the sky is blue or the sky is reddish at the time of sunrise or sunset.

Wave Optics

1. The speed of the yellow light in a certain liquid is 2.4 × 108 m/s. Find the refractive index of the liquid.
a) 6.25
b) 5.73
c) 1.25
d) 9.73
View Answer

Answer: c
Explanation: μ = 𝑐𝑣𝑡
μ = 3 × 1082.4 × 108
μ = 1.25

2. The wavelength of light coming from a sodium source is 589 nm. What will be its wavelength in the water?
a) 625 nm
b) 443 nm
c) 789 nm
d) 125 nm
View Answer

Answer: b
Explanation: λ = 589 nm, μ = 1.33.
Wavelength in water, λW = 𝜆𝜇
λW = 5891.33
λW = 443 nm.

3. A light wave enters from air into glass. How will the energy of the wave be affected?
a) Decreases
b) Increases
c) Remains the same
d) Independent
View Answer

Answer: a
Explanation: When a light wave enters from the air medium into the glass medium, the energy of the wave decreases because a part of the light wave is reflected in the air. Therefore, in this way, energy will be affected.

4. If a wave undergoes refraction, what will be the phase change?

a) 180o
b) 270o
c) 90o
d) 0o
View Answer

Answer: d
Explanation: When a wave undergoes refraction, the phase change will be zero. The phase change is what guides the process. Therefore, no phase change occurs to a wave during refraction.

5. When a wave undergoes reflection at a denser medium, what will be the phase change?
a) 2π radian
b) 0
c) π radian
d) 3π radian
View Answer

Answer: c
Explanation: When a wave is reflected in the rarer medium from the surface of a denser medium, it undergoes a phase change of π radian. Therefore, when a wave undergoes reflection at a denser medium, the phase change will be π radian.

6. Two wave-fronts intersect each other.

a) True
b) False
View Answer

Answer: b
Explanation: No, this statement is false. If they intersect, then there will be two rays or two directions of propagation of energy at the point of intersection which is not possible. Therefore, two wave-fronts do not intersect with each other.

7. A light wave enters from air into glass. How will the frequency of the wave be affected?
a) Increases
b) Remains unchanged
c) Decreases
d) Insignificant
View Answer

Answer: b
Explanation: The frequency of the wave remains unchanged. This is because the frequency is independent of the wave dynamics. Therefore, when a light wave enters from the air medium into the glass medium, the frequency will be the same.

Dual Nature of Radiation and Matter

1. Two beams, one of red light and the other of blue light, of the same intensity are incident on a metallic surface to emit photoelectrons. Which emits electrons of greater frequency?
a) Both
b) Red light
c) Blue light
d) Neither
View Answer

Answer: c
Explanation: From Einstein’s photoelectric equation, we have
12 mv2 = h(v – v0).
Since the frequency of blue light is greater than that of the red light, blue light emits electrons of greater kinetic energy.

2. If the intensity of incident radiation in a photo-cell is increased, how does the stopping potential vary?
a) Increases
b) Remains the same
c) Decreases
d) Infinite
View Answer

Answer: b
Explanation: There is no effect on stopping potential. The intensity of incident radiation is independent of stopping potential. Therefore, even if the incident radiation in a photo-cell is increased, the stopping potential remains unchanged.

3. If the frequency of the incident radiation is equal to the threshold frequency, what will be the value of the stopping potential?
a) 0
b) Infinite
c) 180 V
d) 1220 V
View Answer

Answer: a
Explanation: From Einstein’s photoelectric equation, we have
12 mv2 = h(v – v0).
When v = v0,
hv0 = hv0 + eV0
Therefore, V0 = 0.

4. How does retarding potential vary with the frequency of light causing photoelectric effect?
a) Infinite
b) Zero
c) Decreases
d) Increases
View Answer

Answer: d
Explanation: The stopping potential is directly proportional to the frequency of light.
Hence, the stopping potential increases with an increase in the frequency of the incident light.

5. If the intensity of the radiation incident on a photo-sensitive plate is doubled, how does the stopping potential change?
a) Increases
b) Decreases
c) No effect
d) Infinite
View Answer

Answer: c
Explanation: No effect. This is because the intensity of radiation incident on a photo-sensitive plate is independent on stopping potential. So, the stopping potential remains the same, even if the intensity is doubled.

6. The stopping potential in photoelectric emission does not depend upon the frequency of the incident radiation.
a) True
b) False
View Answer

Answer: b
Explanation: The stopping potential depends on the frequency of incident radiation. Above the threshold frequency, the stopping potential is directly proportional to the frequency of incident radiation.

7. The maximum kinetic energy of a photoelectron is 3 eV. What is the stopping potential?
a) 0 V
b) 3 V
c) 9 V
d) 12 V
View Answer

Answer: b
Explanation: Stopping potential is given as:
V0 = 𝐾𝑚𝑎𝑥𝑒
V0 = 3𝑒𝑉𝑒
V0 = 3 V
Therefore, the stopping potential is 3 V.

8. The stopping potential in an experiment on the photoelectric effect is 1.5 V. What is the maximum kinetic energy of the photoelectrons emitted?
a) 1.5 eV
b) 3 eV
c) 4.5 eV
d) 6 eV
View Answer

Answer: a
Explanation: Kmax = eV0
Kmax = 1.6 × 10-19 C × 1.5 V
Kmax = 24 × 10-19 J
It can also be converted into units of electron volts that will be:
Kmax = 1.5 eV

9. For a photosensitive surface, the work function is 3.3 × 10-19 J. Calculate the threshold frequency.
a) 15 × 1014 Hz
b) 25 × 1014 Hz
c) 5 × 1014 Hz
d) 55 × 1014 Hz
View Answer

Answer: c
Explanation: Threshold frequency is given as:
v0 = 𝑊0ℎ
v0 = 𝑊0ℎ
v0 = (3.3×10−19)(6.6×10−34)
v0 = 5 × 1014 Hz.

10. Calculate the kinetic energy of a photoelectron (in eV) emitted on shining light of wavelength 6.2 × 10-6 m on a metal surface. The work function of the metal is 0.1 eV.
a) 10 eV
b) 0.1 eV
c) 0.01 eV
d) 1000 eV
View Answer

Answer: b
Explanation: Kmax = (ℎ𝑐𝜆) – W0
Kmax = [(6.6×10−34×3×108)(6.2×10−6×1.6×10−19)] – 0.1.
Kmax = 0.2 – 0.1
Kmax = 0.1 eV

Atoms

1. Which source is associated with a line emission spectrum?

a) Electric fire
b) Neon street sign
c) Red traffic light
d) Sun
View Answer

Answer: b
Explanation: Neon street sign gives a line emission spectrum. When neon atoms gain enough energy to become excited, light is produced. Atom releases a photon when it returns to a lower energy state. Therefore, the source associated with a line emission spectrum is the neon street sign.

2. According to the uncertainty principle for an electron, time measurement will become uncertain if which of the following is measured with high certainty?
a) Energy
b) Momentum
c) Location
d) Velocity
View Answer

Answer: a
Explanation: According to the uncertainty principle,
ΔE.Δt >= ℎ2𝜋.
Thus the time measured will become uncertain if ΔE is measured with high certainty.

3. Find the true statement.
a) An electron will not lose energy when jumping from the 1st orbit to the 3rd orbit
b) An electron will not give energy when jumping from the 1st orbit to the 3rd orbit
c) An electron will release energy when jumping from the 1st orbit to the 3rd orbit
d) An electron will absorb energy when jumping from the 1st orbit to the 3rd orbit
View Answer

Answer: d
Explanation: An electron will absorb energy when jumping from the 1st orbit to the 3rd orbit. Only by absorbing energy, an electron will be able to jump from the first orbit to the third orbit in the atomic spectrum.

4. The size of the atom is proportional to which of the following?
a) A
b) A1/3
c) A2/3
d) A-1/3
View Answer

Answer: b
Explanation: The size of the atom is proportional to A1/3.
The electron affinity of the atom is inversely proportional to the atomic size. As the number of energy levels increases, the atomic size must increase.

5. Calculate the ratio of the kinetic energy for the n = 2 electron for the Li atom to that of Be+ ion?
a) 916
b) 34
c) 1
d) 12
View Answer

Answer: a
Explanation: 𝐾𝐸𝐿𝑖𝐾𝐸𝐵𝑒=[(𝑍𝐿𝑖2)(𝑍𝐵𝑒2)]2
𝐾𝐸𝐿𝑖𝐾𝐸𝐵𝑒=[(32)(42)]2
𝐾𝐸𝐿𝑖𝐾𝐸𝐵𝑒=916.

6. The Bohr model of atoms uses Einstein’s photoelectric equation.
a) True
b) False
View Answer

Answer: b
Explanation: Bohr model assumes that the angular momentum of electrons is quantized. Therefore, the Bohr model of the atoms involved is independent of Einstein’s photoelectric equation.

7. What is the ratio of minimum to maximum wavelength in the Balmer series?
a) 5:9
b) 5:36
c) 1:4
d) 3:4
View Answer

Answer: a
Explanation: For a wavelength of Balmer series,
1𝜆 = R[14–19]
1𝜆=5𝑅30.
𝜆𝑚𝑖𝑛𝜆𝑚𝑎𝑥=5𝑅36×4𝑅
𝜆𝑚𝑖𝑛𝜆𝑚𝑎𝑥=59

8. The energy of characteristic X-ray is a consequence of which of the following?
a) The energy of the projectile electron
b) The thermal energy of the target
c) Transition in target atoms
d) Temperature
View Answer

Answer: c
Explanation: The energy of characteristic X-ray is a consequence of transition in target atoms. They cause emission or absorption of electromagnetic radiation. The other options are not responsible for the energy of characteristic X rays.

9. Find out the minimum energy required to take out the only one electron from the ground state of Li+?
a) 13.6 eV
b) 122.4 eV
c) 25.3 eV
d) 67.9 eV
View Answer

Answer: b
Explanation: Ionization energy is given as:
E = 13.6 Z2 eV
For Li+, Z = 3
E = 13.6 × 9
E = 122.4 eV

10. What is the energy required to ionize an H-atom from the third excited state, if ground state ionization energy of H-atom is 13.6 eV?
a) 1.5 eV
b) 3.4 eV
c) 13.6 eV
d) 12.1 eV
View Answer

Answer: a
Explanation: From third excited state, E = −13.616
E = -0.85 eV
Energy required to ionize H-atom from second excited state = 0 – (-0.85)
E = +0.85 eV

Nuclei

1. The neutron was discovered by whom?

a) Marie Curie
b) Pierre Curie
c) Rutherford
d) James Chadwick
View Answer

Answer: d
Explanation: Neutrons are chargeless subatomic particles. It was discovered by James Chadwick in 1932. They are present in all-atom nuclei except those of ordinary hydrogen. The neutron was initially very difficult to detect and therefore, the last to be discovered.

2. The magnetic moment of a revolving electron around the nucleus varies with the principal quantum number as which of the following?
a) μ ∝ n
b) μ ∝ 1𝑛
c) μ ∝ n2
d) μ ∝ 1𝑛2
View Answer

Answer: a
Explanation: L = 𝑛ℎ2𝜋 and μ = 𝑒𝐿2𝑚.
μ = 𝑒𝑛ℎ2𝑚.2𝜋
Therefore, μ ∝ n.

3. Which of the following has the highest neutron ratio?
a) 8O16
b) 2He4
c) 26Fe56
d) 92U235
View Answer

Answer: d
Explanation: The nucleus of Uranium 235(92U235) has 234 – 92 = 142 neutrons.
Therefore, It has the highest proton to neutron ratio, i.e.
= The number of protons: the number of neutrons
= 142:92

4. When a radioactive substance emits an α-particle, its position in the periodic table is lowered by which of the following?
a) One place
b) Two places
c) Three places
d) Four places
View Answer

Answer: b
Explanation: When a radioactive substance emits an α-particle, its atomic number decreases by a factor of 2. Therefore, its position in the periodic table is also lowered by two places.

5. If alpha, beta, and gamma rays carry the same momentum, which has the longest wavelength?
a) Alpha rays
b) Beta rays
c) Gamma rays
d) All have the same wavelength
View Answer

Answer: d
Explanation: Wavelength of de Broglie waves is given as:
λ = ℎ𝑝.
As momentum is the same for all rays, all have the same wavelength λ.

6. β-rays emitted from radioactive material are known as electromagnetic radiation.
a) True
b) False
View Answer

Answer: b
Explanation: No, this is a false statement. β-rays are charged particles emitted by radioactive nuclei. Therefore, these rays are highly energetic electrons that are released from the inside of a nucleus. Thus, these are not electromagnetic radiations.

7. If elements with principal quantum number n > 4 were not allowed in nature, then what will be the number of possible elements?
a) 60
b) 20
c) 4
d) 64
View Answer

Answer: a
Explanation: Maximum number of electrons in an orbit = 2n2.
As n > 4 is not allowed, the number of possible elements = 2(1)2 + 2(2)2 + 2(3)2
Number of possible elements = 2(4)2
Number of possible elements = 60.

8. For uranium nucleus how does its mass vary with volume?
a) m ∝ V
b) m ∝ 1𝑉
c) m ∝ √V
d) m ∝ V2
View Answer

Answer: a
Explanation: Mass of nucleus = Nuclear density × Volume.
The nuclear density of an atom is constant (10-17 kgm-3) for all nuclei, therefore, the mass of the nucleus is directly proportional to the volume.

9. Which of the following is a correct statement?
a) Beta rays are the same as for cathode rays
b) Gamma rays are high energy neutrons
c) Alpha particles are singly ionized helium atoms
d) Protons and neutrons have the same mass
View Answer

Answer: a
Explanation: β-rays are electrons of nuclear origin. Therefore, they have the same nature as the cathode rays. The other statements are not valid.

10. Which is a non-central force?
a) Electrostatic force
b) Nuclear force
c) Gravitational force
d) Spring force
View Answer

Answer: b
Explanation: Nuclear force is a non-central force. They are dependent on the spin of the nuclei, and not on whether the nucleons are protons or neutrons. The tensor force exists between two nucleons, and therefore, it has a tensor component.

Semiconductor Electronics : Materials, Devices and Simple Circuits

1. The manifestation of the band structure in solids is due to which of the following?
a) Heisenberg’s uncertainty principle
b) Pauli’s exclusion principle
c) Bohr’s correspondence principle
d) Boltzmann’s law
View Answer

Answer: b
Explanation: The electronic configuration of atoms and consequently their manifestation of the band structure of solids can be well explained based on Pauli’s exclusion principle.

2. The energy band gap is maximum in which of the following?
a) Metals
b) Superconductors
c) Insulators
d) Semiconductors
View Answer

Answer: c
Explanation: The bandgap is maximum in insulators. This makes it difficult for electrons to move to the conduction band. This is contrary to metals and superconductors, which has minimum band gaps facilitating the movement of electrons.

3. At absolute zero, Si acts as which of the following?
a) Non-metal
b) Metal
c) Insulator
d) Superconductor
View Answer

Answer: c
Explanation: At absolute zero, the element, silicon (Si) acts as an insulator due to the absence of free electrons in the conduction band. The other options are not valid.

4. A piece of copper and another of germanium are cooled from room temperature to 77 K. what will impact on the resistance of each of them?

a) Each of these decreases
b) Copper strip increases and that of germanium decreases
c) Copper strip decreases and that of germanium increases
d) Each of these increases
View Answer

Answer: c
Explanation: With the decrease of temperature, the resistance of copper, which is a metallic conductor, will decrease, whereas the resistance of germanium, which is a semiconductor will increase.

5. In semiconductors at room temperature, which of the following is likely to happen?
a) The valence band is partially empty and the conduction band is partially filled
b) The valence band is filled and the conduction band is partially filled
c) The valence band is filled
d) The conduction band is empty
View Answer

Answer: a
Explanation: In semiconductors at room temperature, the valence band is partially empty and the conduction band is partially filled. The other options are not suitable according to the room temperature condition of semiconductors.

6. At absolute zero temperature, a semiconductor acts as a conductor.
a) True
b) False
View Answer

Answer: b
Explanation: At absolute zero temperature, a semiconductor does act as an insulator. When the electron gains enough energy to participate in conduction, the electron is at a low energy state. Therefore, the semiconductors pretend like an insulator.

7. Which of the following is true regarding insulators?
a) The valence band is partially filled with electrons
b) The conduction band is partially filled with electrons
c) The conduction band is filled with electrons and valence band empty
d) The conduction band is empty and valence band is filled with electrons
View Answer

Answer: a
Explanation: In insulators, the conduction band is empty and the valence band is filled with electrons. The other options do not correspond to the concept of insulators, but rather conductors and semiconductors.

8. Crystalline solids are which of the following?
a) Anisotropic
b) Isotropic
c) Amorphous
d) Unipotential
View Answer

Answer: a
Explanation: Crystalline solids are anisotropic as they show different physical properties in a different direction. Therefore, they are neither isotropic, amorphous, nor unit potential in nature.

9. Which of the following is an amorphous solid?
a) Glass
b) Diamond
c) Salt
d) Sugar
View Answer

Answer: a
Explanation: Glass is an amorphous solid. It is a non-crystalline solid in which the atoms and molecules are not organized in a definite lattice pattern. The other options are crystalline.

10. At which temperature, a pure semiconductor behaves slightly as a conductor?
a) Low temperature
b) Room temperature
c) High temperature
d) Supercritical temperature
View Answer

Answer: c
Explanation: A pure semiconductor behaves slightly as a conductor at high temperatures. Their resistivity decreases as temperature increases. Therefore, at high temperatures, semiconductors slightly act as a conductor.

Communication Systems

1. How many elements are essential for any communication system?
a) 3
b) 2
c) 4
d) 7
View Answer

Answer: a
Explanation: Communication is the very act of transmission of information. Irrespective of its nature, every communication system has three essential elements, namely a transmitter, a medium or channel, and a receiver.

2. Which of the following is the purpose of the transmitter?
a) Converts signals to electric form
b) Operating the received signal
c) Converting the signal into a suitable form
d) Reduces noise from signals
View Answer

Answer: c
Explanation: The purpose of a transmitter is to convert the message signal produced by the source of information into a suitable form that can be transmitted through the channel that connects the transmitter and the receiver.

3. Which among the following can be an input to a transmitter?
a) Voice signal
b) Electric signal
c) Light signal
d) Wave signal
View Answer

Answer: b
Explanation: If the output of the information source is a non-electrical signal such as a voice signal, then that’s where the transducer comes into play. The transducer converts this voice signal into an electric form before giving it as an input to the transmitter.

4. A channel can be either in the form of wires or wireless.
a) True
b) False
View Answer

Answer: a
Explanation: Yes, this is a true statement. Depending upon the type of the communication system, a channel can be in the form of wires or cables connecting the transmitter and the receiver or it can also be wireless.

5. Which of the following is the reason for signal distortion?
a) Speed of the signal
b) Wearing down of the essential elements
c) Absence of a channel
d) Channel imperfection
View Answer

Answer: d
Explanation: Channel imperfection is that the reason for distortion when a transmitted signal propagates along the channel. Moreover, the receiver receives a corrupted version of the transmitted signal thanks to the addition of noise to the transmitted signal.

6. What is the function of the receiver?
a) Converts signal into electric form
b) Reducing noise during transmission
c) Operating on the received signal
d) Converting the signal into a useful form
View Answer

Answer: c
Explanation: The receiver does the function of operating on the received signal. The receiver reconstructs a recognizable form of the original message signal in order to deliver the signal to the user of information.

7. Find the odd one out.
a) Radio
b) Telephone
c) Television
d) Computer networking