Online Physics Quiz 2020 For B. Sc. Sem IV Organized By Department Of Physics, Kamla Nehru Mahavidyalaya, NaGPur

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1/50 Questions

Which of the following axis system is being satisfied by cubic crystal system?
- A = b = c, α = β = γ = 90⁰
- A ≠ b = c, α = β = γ = 90⁰
- A = b ≠ c, α = β = γ = 90⁰
- A = b = c, α ≠ β = ϒ = 90⁰

About This Quiz

B. Sc. Sem IV
Instructions: The Quiz is based on the R. T. M. Nagpur University Syllabus of B. Sc. (Physics). The Quiz consist of total 50 questions. Question no. 1 to 25 based on Physics paper I and Question no. 26 to 50 based on Physics Paper II. All Questions are Compulsory. No negative marking Has a time See morelimit of 120 minutes Has a pass mark of 40% You can download certificate after finishing the quiz.

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2.

X-rays were invented by
- Albert Einstein
- Isaac Newton
- Wilhelm Rontgen
- None of the above
Correct Answer

A. Wilhelm Rontgen

Explanation

Wilhelm Rontgen is credited with the invention of X-rays. In 1895, Rontgen accidentally discovered X-rays while experimenting with cathode rays. He noticed that a fluorescent screen in his lab started to glow even though it was not directly exposed to the cathode rays. Rontgen further investigated this phenomenon and named the newly discovered rays "X-rays". He published his findings and conducted extensive research on X-rays, which led to their widespread use in medical imaging and other fields. Therefore, Wilhelm Rontgen is the correct answer for the inventor of X-rays.

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3.

For satellites the source of energy is
- Solar cell
- Fuel cells
- Edison cells
- Cryogenic storage
Correct Answer

A. Solar cell

Explanation

Satellites rely on solar cells as their source of energy. Solar cells, also known as photovoltaic cells, convert sunlight directly into electricity. This is a practical and efficient method for powering satellites as they are exposed to sunlight while orbiting the Earth. Solar cells are lightweight, durable, and can generate electricity for extended periods, making them ideal for powering satellites in space. Fuel cells, Edison cells, and cryogenic storage are not commonly used as energy sources for satellites.

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4.

Number of atoms per unit cell for FCC structure is
- 1
- 2
- 4
- 0
Correct Answer

A. 4

Explanation

In a face-centered cubic (FCC) structure, each corner of the cube is shared by 8 unit cells, while each face is shared by 2 unit cells. Therefore, each unit cell contains 1/8th of an atom from each corner (8 corners x 1/8th = 1 atom) and 1/2 of an atom from each face (6 faces x 1/2 = 3 atoms). Adding these together gives a total of 4 atoms per unit cell in an FCC structure.

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5.

Electromagnetic light consists of photon each of energy E=hn. Where n is the frequency associatd with each photon then, what ‘h’ stands for in the given equation?
- Gravitation constant
- Planck’s constant
- Permittivity
- Attenuation constant
Correct Answer

A. Planck’s constant

Explanation

The letter 'h' in the given equation stands for Planck's constant. Planck's constant is a fundamental constant in quantum mechanics that relates the energy of a photon to its frequency. It is denoted by the symbol 'h' and has a value of approximately 6.626 x 10^-34 joule-seconds.

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6.

In free space, X-ray travels in ______________
- Periodic oscillations
- Non-Periodic oscillations
- Zig-zag path
- Straight line
Correct Answer

A. Straight line

Explanation

X-rays travel in a straight line in free space because they are electromagnetic waves. Electromagnetic waves, including X-rays, propagate in a straight line unless they encounter an obstacle or are deflected by a medium. This straight line propagation is due to the nature of electromagnetic waves, which consist of oscillating electric and magnetic fields that move perpendicular to each other and the direction of wave propagation. Therefore, X-rays do not exhibit periodic oscillations, non-periodic oscillations, or zig-zag paths, but instead travel in a straight line.

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7.

Mathematically Bragg’s law is stated as-
Correct Answer

A.
8.

The cathode in the Coolidge tube is made of which of the following elements?
- Quartz
- Iron
- Tungsten
- Barium
Correct Answer

A. Tungsten

Explanation

The cathode in the Coolidge tube is made of tungsten. Tungsten is commonly used in cathodes because it has a high melting point, good electron emission properties, and can withstand high temperatures. It is an ideal material for cathodes in X-ray tubes as it can generate a large number of electrons when heated, which are then accelerated towards the anode to produce X-rays. Quartz, iron, and barium are not typically used as cathode materials in Coolidge tubes.

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9.

The process by which atoms are raised from the lower energy level to the upper energy level is called—
- Pumping
- Assembling
- Gathering
- Gearing
Correct Answer

A. Pumping

Explanation

The process described in the question refers to the movement of atoms from a lower energy level to a higher energy level. This process is commonly known as "pumping." The other options mentioned, such as assembling, gathering, and gearing, do not accurately describe the process of raising atoms to higher energy levels.

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10.

The smallest portion of the lattice is known as __________
- Lattice structure
- Lattice point
- Bravais crystal
- Unit cell
Correct Answer

A. Unit cell

Explanation

The smallest portion of the lattice is known as the unit cell. It is a repeating unit that represents the entire lattice structure. The unit cell contains one or more lattice points and possesses the same symmetry as the overall lattice. It is used to describe the arrangement of atoms or ions in a crystal lattice and is essential in understanding the properties and behavior of materials.

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11.

Coordination number for an ideal BCC metallic crystal is:
- 8
- 6
- 12
- Varies for different metals
Correct Answer

A. 8

Explanation

The coordination number for an ideal BCC metallic crystal is 8. In a BCC structure, each atom is surrounded by 8 neighboring atoms, forming a cube-like arrangement. This means that each atom has 8 nearest neighbors, resulting in a coordination number of 8.

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12.

X-ray crystallography uses which law for its implementation?
- Einstein’s law
- Planck’s law
- Bragg’s law
- Compton law
Correct Answer

A. Bragg’s law

Explanation

X-ray crystallography uses Bragg's law for its implementation. Bragg's law describes the relationship between the angles at which X-rays are diffracted by a crystal lattice and the spacing between the crystal planes. This law allows scientists to analyze the diffraction pattern produced by X-rays passing through a crystal and determine the arrangement of atoms within the crystal. By measuring the angles and intensities of the diffracted X-rays, valuable information about the structure and composition of the crystal can be obtained.

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13.

Which of the following terminals does not belong to the MOSFET?
- Drain
- Gate
- Base
- Source
Correct Answer

A. Base

Explanation

The base terminal does not belong to the MOSFET. The MOSFET is a type of transistor that has three terminals: the source, gate, and drain. The base terminal is typically associated with a different type of transistor called a bipolar junction transistor (BJT). In a MOSFET, the gate terminal is used to control the flow of current between the source and drain terminals. Thus, the base terminal is not part of the MOSFET.

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14.

LASER is acronym for
- Light Accreditation by Stimulated Emission of Radiation
- Light Amplification by Spontaneous Emission of Radiation
- Light Acceleration by Stimulated Emission of Radiation
- Light Amplification by Stimulated Emission of Radiation
Correct Answer

A. Light Amplification by Stimulated Emission of Radiation

Explanation

The correct answer is "Light Amplification by Stimulated Emission of Radiation." LASER is an acronym that stands for Light Amplification by Stimulated Emission of Radiation. This term describes the process by which a laser device produces a highly focused and intense beam of light. In this process, the light is amplified through stimulated emission, where photons are emitted in phase with the incident photons, resulting in a coherent and concentrated beam of light.

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15.

Raman effect is scattering of ________
- Atoms
- Molecules
- Protons
- Photons
Correct Answer

A. Photons

Explanation

The Raman effect is the scattering of photons. When light interacts with a material, some of the photons can undergo a change in energy and wavelength. This change is caused by the interaction between the photons and the vibrational or rotational modes of the material's molecules. This phenomenon, known as the Raman effect, provides valuable information about the molecular structure and dynamics of the material being studied.

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16.

The total angular quantum number (J) is given by____(Where L & S are Orbital & Spin quantum numbers respectively)
- J = L + S
- J = L - S
- J = L/S
- J = L x S
Correct Answer

A. J = L + S

Explanation

The total angular quantum number (J) is given by adding the orbital quantum number (L) and the spin quantum number (S). This is because the total angular momentum of an atom or particle is the sum of the orbital angular momentum and the spin angular momentum. Therefore, the correct answer is J = L + S.

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17.

A longer-lived upper energy level in an atom where atom remain excited for appreciable time is known as--
- Mega-stable state
- Mini-stable state
- Multistable state
- Metastable state
Correct Answer

A. Metastable state

Explanation

A metastable state refers to a longer-lived upper energy level in an atom where the atom remains excited for a significant amount of time. Unlike stable states, which quickly transition to lower energy levels, metastable states have a longer lifetime before returning to their ground state. This is due to certain restrictions or barriers that prevent the atom from easily transitioning to a lower energy level. As a result, atoms in a metastable state can retain their excited state for an appreciable period, making it an accurate description for the given scenario.

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18.

The different types of energies associated with a molecule are __________
- Electronic energy
- Vibrational energy
- Rotational energy
- All of the mentioned
Correct Answer

A. All of the mentioned

Explanation

The different types of energies associated with a molecule include electronic energy, vibrational energy, and rotational energy. Electronic energy refers to the energy associated with the movement of electrons within the molecule. Vibrational energy is the energy associated with the vibration of the atoms within the molecule. Rotational energy is the energy associated with the rotation of the molecule as a whole. Therefore, all of these energies are associated with a molecule.

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19.

What should be the biasing of the LED?
- Forward bias
- Reverse bias
- Forward bias than Reverse bias
- No biasing required
Correct Answer

A. Forward bias

Explanation

The LED should be forward biased in order to allow current to flow through it and emit light. In forward bias, the positive terminal of the power supply is connected to the anode of the LED, while the negative terminal is connected to the cathode. This allows the electrons and holes to recombine at the junction, releasing energy in the form of light. Reverse biasing, on the other hand, prevents current flow and does not allow the LED to emit light. No biasing is required means that the LED will not work without any external voltage applied.

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20.

With respect to rotational symmetry operation which of the following symmetry is not possible
- 5-fold symmetry
- 6-fold symmetry
- 4-fold symmetry
- 3-fold symmetry
Correct Answer

A. 5-fold symmetry

Explanation

5-fold symmetry is not possible with respect to rotational symmetry operations. This is because a 5-fold symmetry requires dividing a circle into 5 equal parts, which cannot be achieved with any combination of rotations. In rotational symmetry, an object should be able to be rotated by a certain angle and still remain unchanged. However, no angle of rotation can divide a circle into 5 equal parts, making 5-fold symmetry impossible.

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21.

A JFET is also called …………… transistor
- Unipolar
- Bipolar
- Unijunction
- None of the above
Correct Answer

A. Unipolar

Explanation

The correct answer is "Unipolar." A JFET (Junction Field Effect Transistor) is called a unipolar transistor because its operation is based on the movement of majority charge carriers (either electrons or holes) in a single type of semiconductor material. Unlike bipolar transistors that rely on the movement of both majority and minority charge carriers, JFETs only use one type of charge carrier for their operation.

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22.

The Duane-Hunt rule is analytically expressed as---- (Where e-charge on electron, V-voltage applied, n is the frequency of light radiation and h is Plank's constant)
- EV = hn_max
- En_max = hV
- E / V = h / n_max
- EV = 2 hn_max
Correct Answer

A. EV = hn_max

Explanation

The given equation eV = hnmax represents the Duane-Hunt rule. This equation relates the energy of an electron (eV) to the maximum frequency of light radiation (nmax). It states that the product of the electron charge (e) and the applied voltage (V) is equal to the product of Planck's constant (h) and the maximum frequency of light radiation (nmax). This equation is used to calculate the energy of electrons in a system when the maximum frequency of light radiation is known.

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23.

The two important advantages of a JFET are
- High input impedance and low noise level
- Inexpensive and high output impedance
- Low input impedance and high output impedance
- None of the above
Correct Answer

A. High input impedance and low noise level

Explanation

A JFET (Junction Field-Effect Transistor) has high input impedance, meaning that it does not draw much current from the input source, allowing for efficient signal transfer. Additionally, JFETs have low noise levels, meaning that they introduce minimal unwanted electrical signals or interference into the circuit. These advantages make JFETs suitable for applications requiring high sensitivity and low signal distortion, such as in amplifiers or audio equipment.

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24.

A unique property of LASER is-
- Directional
- Speed
- Coherence
- Wavelength
Correct Answer

A. Coherence

Explanation

Coherence is a unique property of LASER. Coherence refers to the ability of the light waves emitted by a LASER to maintain a constant phase relationship with each other. This means that the waves are in sync and have a consistent pattern, resulting in a highly focused and concentrated beam of light. Coherence is essential for the laser's ability to produce a narrow beam that can travel long distances without spreading out. This property allows lasers to be used in various applications such as telecommunications, medicine, and manufacturing.

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25.

In a transistor ………………..
- IC = IE + IB
- IB = IC + IE
- IE = IC – IB
- IE = IC + IB
Correct Answer

A. IE = IC + IB

Explanation

The given equation, IE = IC + IB, represents the relationship between the emitter current (IE), collector current (IC), and base current (IB) in a transistor. This equation shows that the total emitter current is equal to the sum of the collector current and base current. It is a fundamental equation in transistor analysis and is used to understand the behavior and characteristics of transistors in electronic circuits.

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26.

Which of the following theory explain Raman effect satisfactorily
- Classical Theory
- Quantum Theory
- Langevin Theory
- None of the above
Correct Answer

A. Quantum Theory

Explanation

Quantum Theory is the correct answer because it provides a satisfactory explanation for the Raman effect. The Raman effect refers to the inelastic scattering of light, where the scattered light undergoes a change in wavelength. This phenomenon can be explained by the interaction between light and the vibrational modes of molecules. Quantum Theory accurately describes the behavior of particles and their interactions, including the interaction between photons and molecules in the Raman effect. Classical Theory and Langevin Theory do not provide a satisfactory explanation for this phenomenon.

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27.

Which of the following statement is true
- He-Ne laser is two level laser system
- He-Ne laser is semiconductor laser
- He-Ne laser is a Gas laser
- He-Ne laser emits polychromatic light
Correct Answer

A. He-Ne laser is a Gas laser

Explanation

The He-Ne laser is a gas laser because it uses a mixture of helium and neon gas as the active medium. Gas lasers work by exciting the gas atoms or molecules to higher energy levels, which then emit light when they return to their ground state. In the case of the He-Ne laser, the helium-neon gas mixture is excited by an electrical discharge, and it emits a red laser light with a wavelength of 632.8 nanometers.

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28.

The relation between wavelength, frequency and velocity of the wave is
Correct Answer

A.

Explanation

The relation between wavelength, frequency, and velocity of a wave is given by the equation: wavelength = velocity / frequency. This equation states that the wavelength of a wave is inversely proportional to its frequency and directly proportional to its velocity. In other words, as the frequency of a wave increases, its wavelength decreases, and vice versa. Additionally, as the velocity of a wave increases, its wavelength also increases. This equation is fundamental in understanding the behavior and characteristics of waves in various contexts such as light, sound, and electromagnetic waves.

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29.

Raman effect is analogues to which effect
- Meissner effect
- Zeeman effect
- Compton effect
- Stark effect
Correct Answer

A. Compton effect

Explanation

The Raman effect is analogous to the Compton effect. Both effects involve the interaction of photons with matter. In the Raman effect, a photon is scattered by a molecule, resulting in a change in its energy and wavelength. Similarly, in the Compton effect, a photon interacts with an electron, causing it to recoil and resulting in a change in the photon's energy and wavelength. Both effects provide valuable information about the nature of matter and have been extensively studied in the field of quantum mechanics.

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30.

X-ray crystallography uses which characteristic of light?
- Polarization
- Interference
- Diffraction
- Coherency
Correct Answer

A. Diffraction

Explanation

X-ray crystallography uses the characteristic of diffraction to study the structure of crystals. When X-rays pass through a crystal, they interact with the atoms in the crystal lattice, causing the X-rays to diffract or scatter. By measuring the angles and intensities of the diffracted X-rays, scientists can determine the arrangement of atoms within the crystal and obtain valuable information about its structure. Diffraction is a fundamental property of light that allows X-ray crystallography to provide detailed insights into the atomic and molecular structures of various materials.

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31.

The base of a transistor is ………….. doped
- Heavily
- Moderately
- Lightly
- None of the above
Correct Answer

A. Lightly

Explanation

The base of a transistor is lightly doped. This is because the base region is responsible for controlling the flow of current between the emitter and collector regions. By lightly doping the base, the transistor can achieve a higher gain and better control over the current flow. Additionally, the lightly doped base helps to minimize the recombination of charge carriers, improving the overall efficiency of the transistor.

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32.

Wave number corresponding to particular energy state is given by
Correct Answer

A.

Explanation

The wave number corresponding to a particular energy state is given by the equation that relates the energy of a photon to its wavelength. This equation is known as the Planck-Einstein relation, which states that the energy of a photon is equal to Planck's constant (h) multiplied by the speed of light (c), divided by the wavelength of the photon. Therefore, the wave number (k) can be calculated by dividing the energy of the photon by Planck's constant.

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33.

Bragg’s X-ray spectrometer are not used to identify the physical properties of which of the following?
- Metals
- Liquids
- Polymeric materials
- Solids
Correct Answer

A. Liquids

Explanation

Bragg's X-ray spectrometer is not used to identify the physical properties of liquids because liquids do not have a regular and ordered atomic structure like solids. X-ray spectrometry relies on the diffraction of X-rays by the crystal lattice of a material to determine its physical properties. Liquids do not have a fixed arrangement of atoms and therefore do not produce the characteristic diffraction pattern that can be analyzed by the spectrometer.

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34.

In computer printers _________ laser is used
- He–Ne gas
- Ruby
- Semiconductor
- CO₂
Correct Answer

A. Semiconductor

Explanation

In computer printers, semiconductor lasers are commonly used. Semiconductor lasers are compact and efficient, making them suitable for use in small devices like printers. They are also capable of producing high-quality prints with precise and sharp details. Additionally, semiconductor lasers can be easily modulated, allowing for faster printing speeds. Overall, semiconductor lasers are a popular choice for computer printers due to their size, efficiency, and printing capabilities.

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35.

How many degrees of freedom does a chemical compound of N atoms have?
- 2N
- 2N + 1
- 3N
- 3N + 1
Correct Answer

A. 3N

Explanation

A chemical compound of N atoms has 3 degrees of freedom for each atom, which accounts for the translational, rotational, and vibrational motion. Since there are N atoms, the total number of degrees of freedom is 3N.

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36.

According to Moseley’s Law “The frequency of a given characteristic X-ray line ____________regularly with the increase in atomic number of the element.”
- Decreases
- Remains constant
- Increases
- None of the above
Correct Answer

A. Increases

Explanation

Moseley's Law states that the frequency of a given characteristic X-ray line increases regularly with the increase in atomic number of the element. This means that as the atomic number of an element increases, the frequency of its characteristic X-ray line also increases. Therefore, the correct answer is "Increases".

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37.

Band gap energy of silicon semiconductor is
- 0.7 eV
- 0.7 V
- 0.3 V
- 1.1 eV
Correct Answer

A. 1.1 eV

Explanation

The band gap energy of silicon semiconductor is 1.1 eV. The band gap energy refers to the energy difference between the valence band and the conduction band in a semiconductor material. It determines the energy required for an electron to move from the valence band to the conduction band, thus allowing the material to conduct electricity. In the case of silicon, the band gap energy of 1.1 eV indicates that it is a moderate semiconductor, neither a good conductor nor a good insulator.

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38.

For an n-channel FET, What is the direction of current flow?
- Source to drain
- Drain to source
- Gate to source
- Gate to drain
Correct Answer

A. Drain to source

Explanation

For an n-channel FET, the direction of current flow is from the drain terminal to the source terminal. This is because in an n-channel FET, the channel is formed by the flow of electrons from the source to the drain when a positive voltage is applied to the gate terminal. Therefore, the current flows in the opposite direction, from the drain to the source.

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39.

Moment of inertia of polyatomic molecule is ________ that of diatomic molecule
- Equal to
- Less than
- Greater than
- None of the above
Correct Answer

A. Greater than

Explanation

The moment of inertia of a polyatomic molecule is greater than that of a diatomic molecule. This is because a polyatomic molecule consists of three or more atoms, which are distributed in space and can rotate around multiple axes. This distribution of mass results in a larger moment of inertia compared to a diatomic molecule, which consists of only two atoms and has a simpler rotational motion.

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40.

It has been observed that Raman spectra occur due to changes in
- The Molecular states
- An Atomic state
- Both Atomic and Molecular state
- None of the above
Correct Answer

A. The Molecular states

Explanation

Raman spectra occur due to changes in the molecular states. Raman spectroscopy is a technique that involves the interaction of light with molecules, causing the molecules to undergo vibrational or rotational changes. These changes in molecular states result in the Raman spectra, which provide information about the molecular structure and composition. Atomic states alone do not contribute to Raman spectra, as Raman scattering primarily involves the interaction of light with molecular vibrations. Therefore, the correct answer is the molecular states.

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3
41.

Miller indices for plane having intercept 3a, 3b, 2c with respective X, Y, Z axes are-
- (323)
- (223)
- (332)
- (333)
Correct Answer

A. (223)

Explanation

The Miller indices (223) represent a plane that intersects the X-axis at 2/3 of the unit cell length, the Y-axis at 2/2 or the full unit cell length, and the Z-axis at 3/2 of the unit cell length. This can be visualized as a plane that cuts through the unit cell at specific fractional coordinates along each axis.

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42.

The main application of the enhancement mode MOSFET is :
- Amplification
- Switching
- Tuning
- Rectification
Correct Answer

A. Switching

Explanation

The main application of the enhancement mode MOSFET is switching. Enhancement mode MOSFETs are designed to operate in the "on" or "off" state, making them ideal for switching applications where a signal needs to be turned on or off rapidly. They have a high input impedance and low output impedance, allowing them to efficiently control the flow of current. This makes them suitable for applications such as power supplies, motor control, and digital logic circuits where fast switching is required.

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43.

The Raman spectrum is said to consist of Strokes lines when ________
- Δv > 0
- Δv < 0
- Δv = 0
- Does not depend on Δv
Correct Answer

A. Δv > 0

Explanation

The Raman spectrum is said to consist of Stokes lines when there is a positive shift in the frequency (Δv > 0). Stokes lines occur when the scattered light has less energy than the incident light, indicating that the molecule has gained energy from the interaction with the incident light. This shift in frequency is known as the Raman shift and is a characteristic feature of the Raman spectrum.

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44.

Each point in a reciprocal lattice corresponds to----
- A particular set of perpendicular planes of the direct lattice
- A particular set of parallel planes of the direct lattice
- A particular set of similar planes of the direct lattice
- None of the above
Correct Answer

A. A particular set of parallel planes of the direct lattice

Explanation

Each point in a reciprocal lattice corresponds to a particular set of parallel planes of the direct lattice. The reciprocal lattice is a mathematical construct that is used to describe the periodicity of a crystal lattice in reciprocal space. The points in the reciprocal lattice are related to the planes in the direct lattice through the reciprocal lattice vector. These planes in the direct lattice are parallel to each other and are represented by the points in the reciprocal lattice. Therefore, the correct answer is "A particular set of parallel planes of the direct lattice."

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45.

A light emitting diode is _________
- Heavily doped
- Lightly doped
- Intrinsic semiconductor
- Zener diode
Correct Answer

A. Heavily doped

Explanation

A light emitting diode is heavily doped because it is designed to emit light when current passes through it. Doping refers to the process of intentionally adding impurities to a semiconductor material to modify its electrical properties. In the case of a LED, the semiconductor material is heavily doped with impurities to create a p-n junction, which allows the LED to emit light when forward biased.

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46.

Thermal stability of transistor can be obtained by_________
- Shifting operating point
- Increasing power supply
- Heat sink
- Decreasing current at collector
Correct Answer

A. Heat sink

Explanation

A heat sink is a device that helps dissipate heat generated by a transistor, thereby improving its thermal stability. When a transistor operates, it generates heat due to the flow of current. If this heat is not properly dissipated, it can cause the transistor to overheat, leading to a decrease in performance and potentially damaging the device. By using a heat sink, the excess heat is transferred away from the transistor, allowing it to operate at a lower temperature and improving its stability.

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1
47.

Which of the following is NOT a correct aspect of the Born-Oppenheimer approximation
- The electrons in a molecule move much faster than the nuclei.
- Excited electronic states have the same equilibrium internuclear distance as the ground electronic state.
- The electronic and vibrational motions of a molecule are approximately separable.
- Electronic energy curves serve as potential energy functions for nuclear vibrational motion
Correct Answer

A. Excited electronic states have the same equilibrium internuclear distance as the ground electronic state.

Explanation

The Born-Oppenheimer approximation states that the electronic and nuclear motions in a molecule can be treated separately. This means that the electrons move much faster than the nuclei, so the statement "The electrons in a molecule move much faster than the nuclei" is a correct aspect of the Born-Oppenheimer approximation. Additionally, the approximation assumes that the electronic and vibrational motions of a molecule are approximately separable, meaning they can be treated independently. It also states that the electronic energy curves serve as potential energy functions for nuclear vibrational motion. However, the statement "Excited electronic states have the same equilibrium internuclear distance as the ground electronic state" is not a correct aspect of the Born-Oppenheimer approximation.

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48.

X-ray lies in which region of the electromagnetic spectrum?
- 10 Å to 7000 Å
- 4000 Å to 10 Å
- 10 Å to 0.01 Å
- 1 Å to 10 Å
Correct Answer

A. 10 Å to 0.01 Å

Explanation

X-rays lie in the region of the electromagnetic spectrum ranging from 10 Å to 0.01 Å. This range is known as the X-ray region, which has shorter wavelengths and higher energy than visible light. X-rays are used in various fields such as medicine, industry, and research for their ability to penetrate through objects and provide detailed images.

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49.

In which of the following method of diffraction the X-ray of continuous type are used?
- Rotating crystal
- Powder
- Laue
- None of the above
Correct Answer

A. Laue

Explanation

The Laue method of diffraction uses X-rays of continuous type. In this method, a crystal is placed in the path of an X-ray beam and the resulting diffraction pattern is observed. The continuous type X-rays used in this method have a wide range of wavelengths, allowing for a more detailed analysis of the crystal structure. The rotating crystal and powder methods, on the other hand, use monochromatic X-rays, which have a single wavelength. Therefore, the correct answer is Laue.

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Online Physics Quiz 2020 For B. Sc. Sem IV Organized By Department Of Physics, Kamla Nehru Mahavidyalaya, NaGPur

Which of the following axis system is being satisfied by cubic crystal system?

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X-rays were invented by

For satellites the source of energy is

Number of atoms per unit cell for FCC structure is

Electromagnetic light consists of photon each of energy E=hn. Where n is the frequency associatd with each photon then, what ‘h’ stands for in the given equation?

In free space, X-ray travels in ______________

Mathematically Bragg’s law is stated as-

The cathode in the Coolidge tube is made of which of the following elements?

The process by which atoms are raised from the lower energy level to the upper energy level is called—

The smallest portion of the lattice is known as __________

Coordination number for an ideal BCC metallic crystal is:

X-ray crystallography uses which law for its implementation?

Which of the following terminals does not belong to the MOSFET?

LASER is acronym for

Raman effect is scattering of ________

The total angular quantum number (J) is given by____(Where L & S are Orbital & Spin quantum numbers respectively)

A longer-lived upper energy level in an atom where atom remain excited for appreciable time is known as--

The different types of energies associated with a molecule are __________

What should be the biasing of the LED?

With respect to rotational symmetry operation which of the following symmetry is not possible

A JFET is also called …………… transistor

The Duane-Hunt rule is analytically expressed as---- (Where e-charge on electron, V-voltage applied, n is the frequency of light radiation and h is Plank's constant)

The two important advantages of a JFET are

A unique property of LASER is-

In a transistor ………………..

Which of the following theory explain Raman effect satisfactorily

Which of the following statement is true

The relation between wavelength, frequency and velocity of the wave is

Raman effect is analogues to which effect

X-ray crystallography uses which characteristic of light?

The base of a transistor is ………….. doped

Wave number corresponding to particular energy state is given by

Bragg’s X-ray spectrometer are not used to identify the physical properties of which of the following?

In computer printers _________ laser is used

How many degrees of freedom does a chemical compound of N atoms have?

According to Moseley’s Law “The frequency of a given characteristic X-ray line ____________regularly with the increase in atomic number of the element.”

Band gap energy of silicon semiconductor is

For an n-channel FET, What is the direction of current flow?

Moment of inertia of polyatomic molecule is ________ that of diatomic molecule

It has been observed that Raman spectra occur due to changes in

Miller indices for plane having intercept 3a, 3b, 2c with respective X, Y, Z axes are-

The main application of the enhancement mode MOSFET is :

The Raman spectrum is said to consist of Strokes lines when ________

Each point in a reciprocal lattice corresponds to----

A light emitting diode is _________

Thermal stability of transistor can be obtained by_________

Which of the following is NOT a correct aspect of the Born-Oppenheimer approximation

X-ray lies in which region of the electromagnetic spectrum?

In which of the following method of diffraction the X-ray of continuous type are used?