MP PSC AP 25-26 Answer Key Physics (Part 1: Q1–50)
MPPSC Assistant Professor Exam 2025-26, Paper II – Physics (Booklet AP/2325/2025-B). Questions 1 to 50 with all options and answer key after every 5 questions.
Questions 1 – 5
For the circuit shown below, determine the current I. Assume silicon diodes with a forward voltage drop of 0.7 V. (E₁ = 20 V → 2.2 kΩ resistor → two silicon diodes in anti-parallel → E₂ = 4 V)
- A7.27 mA
- B10.90 mA
- C5.27 mA
- D6.95 mA
In a universal shift register, the input labelled DSR is used when
- AS₀ = 1, S₁ = 1
- BS₀ = 0, S₁ = 1
- CS₀ = 1, S₁ = 0
- DS₀ = 0, S₁ = 0
The operating principle of a Gunn diode is based on
- AAvalanche multiplication
- BTunnel effect
- CTransferred electron effect
- DPhoto conductivity
A 4-bit synchronous (parallel) counter has a flip-flop propagation delay of 50 ns and a maximum logic path containing one AND gate with a propagation loss delay of 20 ns. Determine the maximum operating frequency (fmax) of the counter.
- A50 MHz
- B10 MHz
- C14.3 MHz
- D20.2 MHz
The maximum power conversion efficiency (η) of a solar cell is best represented by which of the following expression? (Where : VOC = Open Circuit Voltage ; ISC = Short Circuit Current ; ff = fill factor ; Pin = incident solar power)
- Aη = (VOC × ISC) / Pin
- Bη = (VOC × ISC × ff) / Pin
- Cη = Pin / (VOC × ISC × ff)
- Dη = ff / (VOC × ISC)
Questions 6 – 10
The magnetic susceptibility (χ′m) is related to the magnetic permeability μ′ through the expression (in CGS system)
- Aχ′m = (1/4π)(1 − μ′)
- Bχ′m = (1/4π)(μ′ − 1)
- Cχ′m = (1/2π)(1 − μ′)
- Dχ′m = (1/2π)(μ′ − 1)
The magnetic moment of diamagnetic material is given by (e-charge of electron, m-mass of electron, r-radius of orbit, H-magnetic field applied to the normal of the orbit)
- Aμm = + (e²/4m) μ₀ r² H
- Bμm = + (e/2m) μ₀ H
- Cμm = − (e²/4m) μ₀ r² H
- Dμm = − (e/2m) μ₀ H
Magnetic field H is measured in 1 amp-turn/m is equivalent to how many oersteds?
- A4π/10³
- B2π/10³
- Cπ/10³
- Dπ/(2×10³)
Curie-Weiss law is given by (Given C′ − Curie constant)
- Aχm = (C′ − T)/θ
- Bχm = C′/(T + θ)
- Cχm = C′/(T − θ)²
- Dχm = C′/(T − θ)
Specific heat (Cv) at constant volume is given by the relation
- ACv = (∂E/∂T)v
- BCv = (∂T/∂E)v
- CCv = (∂E/∂T)v²
- DCv = (∂T/∂E)²
Questions 11 – 15
Eddy currents are induced in
- AInsulating materials
- BSuperconductors
- CConducting materials exposed to a non-uniform magnetic field
- DVacuum
An infinitely long wire carries a current of 1 A. What will be the value of magnetic field due to it at a distance of 2 cm from the wire? (μ₀ = 4π × 10⁻⁷ MKS)
- A10⁻⁷ T
- B10⁻⁵ T
- C10⁻⁹ T
- D2π × 10⁻⁵ T
Magnetic field due to a current I carrying circular loop at its center is B. Now if the current through the loop is reduced to half, the magnetic field
- ADoubles
- BAlso becomes half
- CBecomes four times
- DDoesn’t change
Poisson’s equation in terms of the vector potential and the current density is given by ∇²A⃗ = −μ₀J⃗. If J⃗ → 0 at infinity, the solution of this equation is of the type
- AA⃗(r⃗) = ∫ [J⃗(r′)/r] dτ′
- BA⃗(r⃗) = (μ₀/4π) ∫ [J⃗(r′)/r] dτ′
- CA⃗(r⃗) = (μ₀/4π) ∫ [J⃗(r′)/r²] dτ′
- DA⃗(r⃗) = ∫ [J⃗(r′)/r²] dτ′
The magnetic flux associated with a loop is given by φ = 4 cos 5πt, where t is in second and φ is in Wb. The maximum magnitude of the emf induced in it at t = 1.5 s will be _______ V.
- A20π
- B10√3 π
- C10π
- D0
Questions 16 – 20
A triangular waveform varying from −5 V to +5 V is applied to the non-inverting (+) input of an op-amp comparator. The inverting input is held at +2 V. The output waveform will
- AAlways remain high
- BAlways remain low
- CThe output waveform will go to positive saturation level only when the input voltage is greater than +2 V
- DSwitch to the negative saturation level only when the input exceeds +2 V
Calculate the output voltage for the circuit of figure. The inputs are V₁ = 50 mV sin(1000t) and V₂ = 10 mV sin(3000t). (Inverting summing amplifier using IC 741: Rf = 330 kΩ, R₁ = 33 kΩ for V₁, R₂ = 10 kΩ for V₂, supply ±9 V)
- A−[0.5 sin(1000t) + 0.33 sin(3000t)] V
- B[0.5 sin(1000t) + 0.33 sin(3000t)] V
- C[0.33 sin(1000t) + 0.5 sin(3000t)] V
- D−[0.33 sin(1000t) + 0.5 sin(3000t)] V
Which addressing mode is used in the instruction MVI A, # 55 H?
- ADirect Addressing
- BImmediate Addressing
- CRegister Indirect Addressing
- DIndexed Addressing
Which of the following correctly describes the Data Bus Width and the Program Counter (PC) width of the standard 8051 microcontroller?
- A4-bit data bus and 8-bit program counter
- B16-bit data bus and 32-bit program counter
- C16-bit data bus and 8-bit program counter
- D8-bit data bus and 16-bit program counter
Which of the following 8085 microprocessor instructions does not affect any of the status flags?
- AADD B
- BMOV A, B
- CANA C
- DCMP D
Questions 21 – 25
If the x, y co-ordinates are rotated counter clockwise through an angle φ, keeping r⃗ fixed the transformed x-component is
- Ax′ = x cosφ + y sinφ
- Bx′ = x cosφ − y sinφ
- Cx′ = x sinφ + y cosφ
- Dx′ = y cosφ − x sinφ
Matrices are primarily used to represent
- AScalar quantities
- BLinear operators or maps
- CDifferential equations only
- DComplex numbers only
An eigenvector of a matrix is a vector that
- AChanges both magnitude and direction after transformation
- BRemains unchanged in both magnitude and direction after transformation
- CChanges only by a scalar factor under the transformation
- DAlways becomes zero
Which of the following equations contain a source term −ρ/ε₀? (Where symbols have their usual meanings)
- ALaplace’s equation
- BHelmholtz’s equation
- CPoisson’s equation
- DDiffusion equation
The standard generating function for Bessel’s functions of integral order is
- Aext
- Be(x/2)(t − 1/t)
- Ce−xt
- Dex²
Questions 26 – 30
The contribution of Coulomb energy in the semi-empirical mass formula of a nucleus of mass number A and atomic number Z is of the form (a = constant)
- AaZA2/3
- BaZ(Z − 1)/A1/3
- CaZ(Z + 1)/A
- DaZ²/A2/3
Given that ₃Li⁷ = 7.01816 amu, ₃Li⁶ = 6.01692 amu, ₀n¹ = 1.00893 amu. The binding energy of a neutron in a ₃Li⁷ nucleus is
- A0.51 meV
- B1.04 meV
- C2.08 meV
- D7.17 meV
Volume of a nucleus in an atom is proportional to the
- AMass number
- BProton number
- CNeutron number
- DElectron number
If the nuclear radius of ²⁷Al is 3.6 Fermi, the approximate nuclear radius of ⁶⁴Cu in Fermi is
- A4.8
- B3.6
- C2.4
- D1.2
Nuclear forces are
- AShort range attractive forces
- BShort range repulsive forces
- CLong range attractive forces
- DLong range repulsive forces
Questions 31 – 35
Rydberg’s constant is
- AR = me⁴ / 8ε₀²ch³
- BR = me⁴ / 4ε₀²ch³
- CR = me⁴ / 16ε₀²ch³
- DR = me⁴ / 2ε₀²ch³
An atom has L = 2, S = 1/2 and J = 3/2, what is its state?
- A²F5/2
- B²F7/2
- C²D1/2
- D²D3/2
A translatory force experienced in Stern-Gerlach experiment is given as
- AFx = (dB/dx) μp cos²θ
- BFx = (dB/dx) μs cosθ
- CFx = (dB/dx) μp sinθ
- DFx = (dB/dx) μs sinθ
The Zeeman shift is denoted as
- Adλ = ± Beλ²/2πmc
- Bdλ = ± Beλ²/8πmc
- Cdλ = ± Beλ²/4πmc
- Ddλ = ± 2Beλ²/πmc
An X-ray machine uses an accelerating potential of 50,000 volts. The shortest wavelength present in X-ray produced is
- Aλmin = 0.248 Å
- Bλmin = 0.148 Å
- Cλmin = 0.348 Å
- Dλmin = 0.082 Å
Questions 36 – 40
According to Bose-Einstein statistics, fBE is equal to
- AA e−ε/kT
- B1 / [eα eε/kT − 1]
- C1 / [eα eε/kT + 1]
- DA e+ε/kT
Three particles are to be distributed in four energy levels a, b, c and d. When particles are bosons, then all possible ways of this distribution are
- A25
- B20
- C22
- D30
_______ is called life time of the microstate. (Where, N = No. of microstates)
- ATmicro = Δx · √(m/KT)
- BTmicro = T/N²
- CTmicro = Vx/Δx
- DNone of these
A molecule of a gas moves equal distances ‘l’ between collisions with equal probability in any direction. After a total of N such displacements, what is the mean square displacement R² of the molecule from its starting point?
- ANl²
- BNl
- CZero
- DNone of these
An ensemble in which each system has the same fixed energy as well as the same number of particles, is called
- ACanonical ensemble
- BMicro canonical ensemble
- CGrand canonical ensemble
- DNone of these
Questions 41 – 45
Consider the following statements about Newton’s laws of motion.
Statement I : Newton’s first law can be understood as a definition of a net force zero.
Statement II : Newton’s first law is essentially a special case of Newton’s second law.
Choose the correct option :
- AOnly statement I is true
- BOnly statement II is true
- CBoth statement I and statement II are true
- DBoth statements are wrong
For conservative force F, consider the following statements.
Statement I : The work done by F in moving a particle between two points is independent of path taken.
Statement II : The work done by F in moving a particle around any closed path is zero.
Statement III : The force F can be expressed as the negative gradient of scalar potential energy function.
Choose the correct option :
- AOnly statement I and II are true
- BOnly statement II and III are true
- COnly statement I and III are true
- DAll the statements are true
How does a one dimensional harmonic oscillator oscillates in phase space?
- Ain straight line
- Bin ellipse
- Cin parabola
- Din hyperbola
Kepler’s second law states that “The radius vector joining a planet to the sun sweeps out area at a rate that is independent of its position in the orbit”. It implies that the
- Aspeed of the planet is constant
- Bangular momentum of planet is conserved
- Cenergy of the planet is constant
- Dradius of the planet is constant
A particle moving in a central force field at r = 0, describes a spiral r = e−θ. The magnitude of force is proportional to
- Ar²
- B1/r²
- Cr³
- D1/r³
Questions 46 – 50
When current through a closed loop is 2 mA, its self-inductance is 25 mH. If the current is doubled, its self-inductance will become
- A50 mH
- B12.5 mH
- C25 mH
- D0 mH
Which of the following equation is a general solution to the Laplace equation in one dimension?
- AV(x) = x²
- BV(x) = Ax + B
- CV(x) = eˣ
- DV(x) = sinx
Which fundamental law of Physics is represented by continuity equation?
- AConservation of energy
- BConservation of linear momentum
- CConservation of angular momentum
- DConservation of electric charge
Let the unit vector along the direction of polarization of transverse electromagnetic wave is n̂ and that in the direction of its propagation is k̂. Then n̂ · k̂ =
- A1
- B0
- Csinθ
- Dcosecθ
The differential equation for a wave, propagating along z-axis, is given by ∂²f/∂z² = 25π² ∂²f/∂t². What is its speed?
- A25π² unit
- B5π unit
- C1/(25π²) unit
- D1/(5π) unit
Answer Key at a Glance (Q1–Q50)
| Q.No. | Answer | Correct Option |
|---|---|---|
| 1 | D | 6.95 mA |
| 2 | C | S₀ = 1, S₁ = 0 |
| 3 | C | Transferred electron effect |
| 4 | C | 14.3 MHz |
| 5 | B | η = (VOC × ISC × ff) / Pin |
| 6 | B | χ′m = (1/4π)(μ′ − 1) |
| 7 | C | μm = − (e²/4m) μ₀ r² H |
| 8 | A | 4π/10³ |
| 9 | D | χm = C′/(T − θ) |
| 10 | A | Cv = (∂E/∂T)v |
| 11 | C | Conducting materials exposed to a non-uniform magnetic field |
| 12 | B | 10⁻⁵ T |
| 13 | B | Also becomes half |
| 14 | B | A⃗(r⃗) = (μ₀/4π) ∫ [J⃗(r′)/r] dτ′ |
| 15 | A | 20π |
| 16 | C | The output waveform will go to positive saturation level only when the input voltage is greater than +2 V |
| 17 | A | −[0.5 sin(1000t) + 0.33 sin(3000t)] V |
| 18 | B | Immediate Addressing |
| 19 | D | 8-bit data bus and 16-bit program counter |
| 20 | B | MOV A, B |
| 21 | A | x′ = x cosφ + y sinφ |
| 22 | B | Linear operators or maps |
| 23 | C | Changes only by a scalar factor under the transformation |
| 24 | C | Poisson’s equation |
| 25 | B | e(x/2)(t − 1/t) |
| 26 | B | aZ(Z − 1)/A1/3 |
| 27 | D | 7.17 meV |
| 28 | A | Mass number |
| 29 | A | 4.8 |
| 30 | A | Short range attractive forces |
| 31 | A | R = me⁴ / 8ε₀²ch³ |
| 32 | D | ²D3/2 |
| 33 | B | Fx = (dB/dx) μs cosθ |
| 34 | C | dλ = ± Beλ²/4πmc |
| 35 | A | λmin = 0.248 Å |
| 36 | B | 1 / [eα eε/kT − 1] |
| 37 | B | 20 |
| 38 | A | Tmicro = Δx · √(m/KT) |
| 39 | A | Nl² |
| 40 | B | Micro canonical ensemble |
| 41 | C | Both statement I and statement II are true |
| 42 | D | All the statements are true |
| 43 | B | in ellipse |
| 44 | B | angular momentum of planet is conserved |
| 45 | D | 1/r³ |
| 46 | C | 25 mH |
| 47 | B | V(x) = Ax + B |
| 48 | D | Conservation of electric charge |
| 49 | B | 0 |
| 50 | D | 1/(5π) unit |
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MP PSC AP 25-26 Answer Key Physics (Part 2: Q51–100)
MPPSC Assistant Professor Exam 2025-26, Paper II – Physics (Booklet AP/2325/2025-B). Questions 51 to 100 with all options and answer key after every 5 questions.
Questions 51 – 55
The sum of Boltzmann factors over all states is called
- APartition function
- BCanonical distribution
- CBoltzmann function
- DNone of these
If the partition function is given by Z, then mean energy Ē is given by
- AĒ = −∂/∂V (log Z)
- BĒ = −∂/∂β (Z)
- CĒ = −∂/∂β (log Z)
- DNone of these
The diffusion co-efficient is directly proportional to
- AP
- BT2/3
- CT3/2
- DT1/2
A system which can exchange only energy with the surroundings is called _______ system.
- AOpen
- BIsolated
- CClosed
- DNone of these
The phenomenon that takes place with no change in entropy and volume at constant temperature and pressure is called _______ order phase transitions.
- ASecond
- BFirst
- CThird
- DFourth
Questions 56 – 60
Fermi factor (where E-energy of allowed state, E₀-Fermi energy) is given by
- A1 / [e(E₀−E)/KT + 1]
- B1 / [e(E−E₀)/KT + 1]
- C1 / [e(E₀−E)/KT − 1]
- D1 / [e(E−E₀)/KT − 1]
The kinetic energy of a free electron is (Quantum mechanical approach) is given as (P-momentum of electron and m is a mass of the electron)
- AE + V = P²/2m
- BE + V = P/2m
- CE − V = P/2m
- DE − V = P²/2m
Fermi energy for intrinsic semiconductors is given by (Where Ev-energy of valence band, Ec-energy of conduction band)
- A(Ev − Ec)
- B(Ev + Ec)
- C½(Ev − Ec)
- D½(Ev + Ec)
The binding (ionization) energy (En) of donor or acceptor impurity levels in an extrinsic semiconductor (The equation obtained from the hydrogen model) is given by (Where symbols have their usual meaning)
- AEn = 2π²m*e⁴ / (n²h²ε²)
- BEn = 2πm*e² / (n²h²ε²)
- CEn = 2πm*e⁴ / (nhε)
- DEn = 2π²m*e² / (n²hε²)
For a typical germanium crystal at room temperature, ne is the order of 2 × 10¹⁵ electron/cm³ and μ = 3600 cm²/(volt-sec), then conductivity is given by (charge of electron = −1.602 × 10⁻¹⁹ C), (Where ne is number of charge carriers and μ is the mobility)
- A~0.5 mho/cm
- B~1.0 mho/cm
- C~4.0 mho/cm
- D~2.9 mho/cm
Questions 61 – 65
The angular momentum of the electron in hydrogen atom can possibly be
- Ah²/4π²
- Bh/2π
- C2π/h
- D1.5h²/π²
Neglecting the variation of mass with velocity, the wavelength associated with an electron having kinetic energy E, is proportional to
- AE1/2
- BE
- CE−1/2
- DE3/2
The uncertainty principle holds for
- AMicroscopic particles only
- BMacroscopic particles only
- CMicroscopic and macroscopic particles both
- DNeither microscopic nor macroscopic particles
The de-Broglie wavelength for an electron of energy 150 eV is
- A10 nm
- B0.1 nm
- C1.0 nm
- D100 nm
The value of the commutator [Lz, L²] is
- A0
- B1
- CLx + Ly
- D2
Questions 66 – 70
The common mode voltage for a differential amplifier is V₀ = 8 V. Given input voltage V₁ = 6 V, then value of other input voltage V₂ is
- A6 V
- B10 V
- C8 V
- D4 V
A 8-bit A/D converter has a full scale analog input voltage of +5 V. For a resolution of 8-bit and full scale error 0.02% of full scale, what is the total possible error?
- A20.607 mV
- B21.607 mV
- C20.202 mV
- D21.202 mV
The latching behaviour of an SCR is primarily due to
- AAvalanche breakdown at the middle junction
- BRegenerative positive feedback between PNP and NPN
- CCapacitive coupling between the gate and cathode
- DReverse leakage current
An eight-bit binary ripple up counter with a modulus of 256 is holding the count 01111111. What will be the count after 135 clock pulses be?
- A11001101
- B00111100
- C01111111
- D00000110
If the average velocity of an electron in GaAs is Vd ≃ 1 × 10⁷ cm/s at a field of 10⁴ V cm⁻¹ and the effective mass of the electron is 0.07 me, the electron mobility (μ) and mean time (t) between electron scattering events will be
- Aμ = 10³ cm²V⁻¹s⁻¹, t = 4 × 10⁻¹⁴ sec.
- Bμ = 5 × 10³ cm²V⁻¹s⁻¹, t = 4 × 10⁻¹⁴ sec.
- Cμ = 10³ cm²V⁻¹s⁻¹, t = 10⁻¹⁴ sec.
- Dμ = 10³ cm²V⁻¹s⁻¹, t = 2 × 10⁻¹⁴ sec.
Questions 71 – 75
Zero-crossing detector is also known as
- ASine wave-to-square wave converter
- BSquare wave-to-sine wave converter
- CTriangle wave-to-sine wave generator
- DSine wave-to-triangle generator
A differential amplifier has +100 mV applied to non-inverting end and +250 mV applied to inverting end. The output is 1.5 V. The gain of the amplifier is
- A10
- B4.29
- C0.6
- D15
A differential amplifier has a common mode gain of 0.02. It has +200 mV signals applied to each of its inputs. The amplitude of output signal is
- A2 mV
- B4 mV
- C8 mV
- D12 mV
Fourier series is for N = 1, 2, 3, …
- Aa₀ + Σ (an sin nx + bn cos nx)
- Ba₀ + Σ (an cos nx + bn sin nx)
- Cb₀ + Σ (an sin nx + bn cos nx)
- Da₀ + b₀ + Σ (an sin x + bn cos x)
The probable error in measuring the horizontal distance x of a tower is ± a and that in measuring its height y is ± b. What will be the probable error in evaluating the tangent of the angle subtended by it at distance x on the ground?
- Aax + by
- B± √(a²y² + b²x²)
- C± √(a²y² + b²x²) / y²
- D± √(b²x² + a²y²) / x²
Questions 76 – 80
The weighting function for the orthogonality of Hermite polynomials is
- A1
- Bx
- Ce−x²
- Dsinx
Which of the following statement is true regarding Fourier series?
- AFourier series are applicable only to non-periodic functions.
- BFourier series are applicable only to periodic functions.
- CFourier coefficients are obtained by differentiation.
- DSine and cosine functions are not orthogonal.
The coefficient of (z − z₀)⁻¹ in Laurent expansion is called the
- APole at z = z₀
- BResidue at z = z₀
- CBranch point at z = z₀
- DSingularity at z = z₀
The transformation philosophy of tensors is based on the fact that
- AMathematical conventions determine physical laws.
- BPhysical predictions should be independent of coordinate systems.
- CCoordinates are always Cartesian.
- DTensor components never change.
A group is called abelian if
- AEvery element has an inverse
- BMultiplication of elements is commutative
- CEvery element is the identity
- DThe group has finite order
Questions 81 – 85
For coupling of three angular momentum 1, 3/2 and 5/2, total number of eigen states will be
- A72
- B24
- C48
- D96
In Born approximation, the cross-section of scattering depends on
- AMomentum p of the incident particle only
- BThe angle of scattering θ only
- CMomentum p and angle θ in any combination
- DMomentum p and angle θ in combination p sin(θ/2)
For the motion of a Dirac particle in a central force field, we have (Where J⃗ = L⃗ + S⃗ and H is the Hamiltonian)
- A[L⃗, H] = 0
- B[S⃗, H] = 0
- C[J⃗, H] = 0
- DAll are true
If α⃗ and β⃗ are Dirac matrices, then the value of (α⃗·β⃗)(α⃗·c⃗) will be (Where c⃗ is arbitrary matrices)
- A0
- B2β⃗·c⃗
- Cβ⃗·c⃗
- D4β⃗·c⃗
According to Quantum mechanics, the energy levels of a particle executing one-dimensional simple harmonic motion are
- AContinuous
- BDiscrete and equispaced
- CDiscrete but not equispaced
- DNothing can be said
Questions 86 – 90
Deuteron is the two nucleon bound system consisting of
- ATwo protons and one electron
- BTwo neutrons and one positron
- COne proton and one neutron with opposite spins
- DOne proton and one neutron with parallel spins
Nuclear forces are
- ASpin dependent and have no non-central part
- BSpin dependent and have a non-central part
- CSpin independent and have no non-central part
- DSpin independent and have a non-central part
The ground state of the deuteron is a
- APure ³S₁ state
- BPure ³P₁ state
- CMixture of ³S₁ and ³P₁ states
- DMixture of ³S₁ and ³D₁ states
According to the shell model, the ground state of ¹⁵₈O nucleus is
- A3/2⁺
- B1/2⁺
- C3/2⁻
- D1/2⁻
The spin and parity of ₄Be⁹ nucleus, as predicted by the shell model, are respectively
- A3/2 and odd
- B1/2 and odd
- C3/2 and even
- D1/2 and even
Questions 91 – 95
The shift in stark effect is denoted as
- A−ΔT = (a₀e / 2zhc) F n(n₂ − n₁)
- B−ΔT = (2a₀e / zhc) F n(n₂ − n₁)
- C−ΔT = (3a₀e / 2zhc) F n(n₂ − n₁)
- D−ΔT = (3a₀e / zhc) F n(n₂ − n₁)
The quantity eh/4π mpc is known as
- ABohr magneton
- BNuclear magneton
- CBohr radius
- DFine structure constant
Stokes and antistokes lines are observed in
- AZeeman effect
- BAnomalous Zeeman effect
- CIsotope shift
- DRaman spectra
In electronic spectra for rotational structure of P-branch, the following statement is true
- AJ′ = J″ + 1
- BJ′ = J″ − 1
- CJ′ = J″
- DJ″ = J′ − 1
The splitting of spectral lines in the presence of magnetic field when the energy due to spin-orbit coupling is less than that due to magnetic field is
- APaschen back effect
- BZeeman effect
- CStark effect
- DRaman effect
Questions 96 – 100
A particle is scattered by a rigid elastic sphere of radius r. What will be the total scattering cross-section?
- Aπr²/2
- Br²/2
- Cπr²
- D4πr²
A rigid body has principal moment of inertia I₁, I₂ and I₃. If I₁ = I₂ and I₃ = 0, then the rigid body is called
- ASpherical top
- BSymmetrical top
- CAsymmetric top
- DRotor
Which quantity is always conserved in torque free motion of a rigid body?
- AAngular momentum
- BRotational kinetic energy
- CBoth (A) and (B)
- DNone of the above
A particle of mass m is attached to a thin uniform rod of length a and mass 4m, at a point located at a distance a/4 from the center of the rod, towards the lower end. The moment of inertia of rod-particle system, about an axis passing through the upper end of the rod and perpendicular to its length will be
- A(67/48) ma²
- B(91/48) ma²
- C(4/3) ma²
- D(19/12) ma²
If the Lagrangian of a mechanical system does not depend explicitly on time, which of the following quantities is conserved?
- AAngular momentum
- BLinear momentum
- CHamiltonian
- DParity
Answer Key at a Glance (Q51–Q100)
| Q.No. | Answer | Correct Option |
|---|---|---|
| 51 | A | Partition function |
| 52 | C | Ē = −∂/∂β (log Z) |
| 53 | C | T3/2 |
| 54 | C | Closed |
| 55 | A | Second |
| 56 | B | 1 / [e(E−E₀)/KT + 1] |
| 57 | D | E − V = P²/2m |
| 58 | D | ½(Ev + Ec) |
| 59 | A | En = 2π²m*e⁴ / (n²h²ε²) |
| 60 | B | ~1.0 mho/cm |
| 61 | B | h/2π |
| 62 | C | E−1/2 |
| 63 | C | Microscopic and macroscopic particles both |
| 64 | B | 0.1 nm |
| 65 | A | 0 |
| 66 | B | 10 V |
| 67 | A | 20.607 mV |
| 68 | B | Regenerative positive feedback between PNP and NPN |
| 69 | D | 00000110 |
| 70 | A | μ = 10³ cm²V⁻¹s⁻¹, t = 4 × 10⁻¹⁴ sec. |
| 71 | A | Sine wave-to-square wave converter |
| 72 | A | 10 |
| 73 | B | 4 mV |
| 74 | B | a₀ + Σ (an cos nx + bn sin nx) |
| 75 | D | ± √(b²x² + a²y²) / x² |
| 76 | C | e−x² |
| 77 | B | Fourier series are applicable only to periodic functions. |
| 78 | B | Residue at z = z₀ |
| 79 | B | Physical predictions should be independent of coordinate systems. |
| 80 | B | Multiplication of elements is commutative |
| 81 | A | 72 |
| 82 | D | Momentum p and angle θ in combination p sin(θ/2) |
| 83 | C | [J⃗, H] = 0 |
| 84 | C | β⃗·c⃗ |
| 85 | B | Discrete and equispaced |
| 86 | D | One proton and one neutron with parallel spins |
| 87 | B | Spin dependent and have a non-central part |
| 88 | D | Mixture of ³S₁ and ³D₁ states |
| 89 | D | 1/2⁻ |
| 90 | A | 3/2 and odd |
| 91 | C | −ΔT = (3a₀e / 2zhc) F n(n₂ − n₁) |
| 92 | B | Nuclear magneton |
| 93 | D | Raman spectra |
| 94 | B | J′ = J″ − 1 |
| 95 | A | Paschen back effect |
| 96 | C | πr² |
| 97 | D | Rotor |
| 98 | C | Both (A) and (B) |
| 99 | B | (91/48) ma² |
| 100 | C | Hamiltonian |
The answers on this page have been collected and prepared with the help of Artificial Intelligence (AI). While we try to keep them accurate, errors or mistakes are possible. This is not an official MPPSC answer key. IrfanEdu.com does not take any responsibility for any wrong answer, correction or change, or for any decision made on the basis of this content.
For final and correct answers, always refer to the official answer key published on the MPPSC website. If you find any mistake, please let us know in the comments so we can correct it.
MP PSC AP 25-26 Answer Key Physics (Part 3: Q101–150)
MPPSC Assistant Professor Exam 2025-26, Paper II – Physics (Booklet AP/2325/2025-B). Questions 101 to 150 with all options and answer key after every 5 questions.
Questions 101 – 105
The modulation index (β) for frequency modulation is defined as
- Aβ = Δf / fm
- Bβ = fm / Δf
- Cβ = Ecmax / fm
- Dβ = Ecmin / Δf
A carrier wave of frequency 10 MHz and peak value 10 V is amplitude modulated by a 5 KHz sine wave of amplitude 6 V. What is the value of modulation index?
- A1.66
- B1.60
- C0.66
- D0.6
A temperature transducers exhibit non-linear behavior. The order in which they exhibit non-linearity (highest to lowest) is
- AThermocouples, RTDs, thermistors
- BThermistors, thermocouples, RTDs
- CRTDs, thermocouples, thermistors
- DThermistors, RTDs, thermocouples
Which of the following optical transducers is an active transducers?
- APhoto-emissive cell
- BPhoto-diode
- CPhoto-transistor
- DPhoto-voltaic cell
From the following data calculate value of y as a linear function of x using method of least squares.
y: 1.2, 2.0, 2.4, 3.5, 3.5
x: 1.0, 1.6, 3.4, 4.0, 5.2
- Ay = 0.24x + 0.872
- By = 0.34x + 0.882
- Cy = 0.44x + 0.810
- Dy = 1.63x − 1.0809
Questions 106 – 110
The solutions of Maxwell's equations
- AAlways obey superposition principle
- BAlways do not obey superposition principle
- CDo not obey superposition principle if dielectric permittivity (ε) depends on electric field (E)
- DAre always non-linear
If for the air-glass interface, n₁ = 1 and n₂ = 1.5, the value of reflection coefficient will be
- A1
- B1.5
- C0.5
- D0.04
When a ray of light is incident on an air-glass interface at Brewster's angle (θp), the angle between the reflected ray and the refracted ray is
- Aθp
- B0°
- C90°
- D180°
_______ waves cannot occur in a hollow wave guide.
- ATEM
- BTE
- CTM
- DTE and TM
A waveguide has a square cross-section of dimensions 3 mm × 3 mm. What will be its cutoff frequency for the TE10 mode?
- A3π Hz
- B3π × 10¹¹ Hz
- C3π × 10³ Hz
- Dπ × 10¹¹ Hz
Questions 111 – 115
If J⃗₁ and J⃗₂ are angular momenta of two non-interacting systems and J⃗ represent the sum of J⃗₁ and J⃗₂ (i.e. J⃗ = J⃗₁ + J⃗₂), then
- AJ₁² and J₂² commute with J² only
- BJ₁² and J₂² commute with Jz only
- CJ₁² and J₂² commute with both J² and Jz
- DJ₁² and J₂² neither commute with J² nor with Jz
A particle is moving in a negative potential field which vanishes at infinity. The spectrum of negative energy eigenvalues of the particle will be
- AContinuous
- BDiscrete
- CContinuous and discrete both
- DContinuous with sudden jumps at a few places
The value of a a⁺ a a⁺a⁺ a
n⟩ would be (Where a
n⟩ = √n
n−1⟩)
- A[n(n+1)]3/2 |n⟩
- B[n(n+1)]3/2 |n+1⟩
- C[n(n+1)]3/2 |n−1⟩
- D[n(n+1)²] |n⟩
The Fermi Golden rule of time dependent perturbation gives the transition of
- APerturbed Hamiltonian from one stationary state to another per unit time
- BPerturbed Hamiltonian from one stationary state to a group of states per unit time
- CPerturbed Hamiltonian from a group of states per unit time
- DNone of these
The first order perturbation energy is given by
- AEn(1) = ⟨n(0)|V|n(0)⟩
- BEn(1) = 0
- CEn(1) = 1
- DEn(1) = ⟨n(1)|V|n(1)⟩
Questions 116 – 120
Hamilton's canonical equations of motion for a conservative system are
- A−dqi/dt = ∂H/∂pi and −dpi/dt = ∂H/∂qi
- Bdpi/dt = ∂H/∂pi and dpi/dt = ∂H/∂qi
- C−dqi/dt = ∂H/∂pi and dpi/dt = ∂H/∂qi
- Ddqi/dt = ∂H/∂pi and −dpi/dt = ∂H/∂qi
A hypothetical train moving with the speed of 0.6C passes by the platform without being slowed down. An observer on the platform note that the length of the train is just equal to the length of the platform which is 200 meter. What is the length of platform as measured by the observer in the train?
- A120 meter
- B160 meter
- C200 meter
- D250 meter
How fast must an electron move in order that its relativistic mass is equal to twice its rest mass?
- A(1/2) C
- B0.707 C
- C(√3/2) C
- D√(3/2) C
The Galilean transformation is obtained from the Lorentz transformation under which of the following conditions?
- Av = c
- Bv > c
- Cv << c
- Dv ≃ c
What is the equivalent mass m of a photon of wavelength λ?
- Am = h/λc
- Bm = λh/c
- Cm = λc/h
- Dm = c/hλ
Questions 121 – 125
Which is Moseley's law?
- Ahν = 2Rhc (z−b)² [1/n₁² − 1/n₂²]
- Bhν = Rhc (z−2b)² [1/n₁² − 1/n₂²]
- Chν = [Rhc (z−b)² / 2] [1/n₁² − 1/n₂²]
- Dhν = Rhc (z−b)² [1/n₁² − 1/n₂²]
The mass of hydrogen atom is 1.6 × 10⁻²⁷ kg. The reduced mass of hydrogen molecule will be
- A4 × 10⁻²⁸ kg
- B6 × 10⁻²⁸ kg
- C8 × 10⁻²⁸ kg
- D8 × 10⁻²⁷ kg
The symbols have their usual meanings. The following relation is obeyed in LASER
- AA₂₁/B₂₁ ∝ ν
- BA₂₁/B₂₁ ∝ ν²
- CA₂₁/B₂₁ ∝ ν³
- DA₂₁/B₂₁ ∝ ν⁴
For fine structure of X-ray levels, the energy of the system is given as
- AT = R(z−b)²/n²
- BT = R(z−b)/n²
- CT = R(z−b)/n
- DT = R(z−b)²/n
The value of Rydberg constant for heavy mass (M) is RM and thus following order is correct, for variation of RM with mass number
- AO¹⁶ > Li⁷ (For both)
- BO¹⁶ < Li⁷ (For both)
- CO¹⁶ = Li⁷ (For both)
- DO¹⁶ ≤ Li⁷ (For both)
Questions 126 – 130
The transformation of ice into water at 0°C and 1 atmospheric pressure is an example of _______ order phase transition.
- AThird
- BSecond
- CFirst
- DNone of these
The entropy S in terms of partition function Z and the mean energy Ē are related with the expression
- AS = K(Z + βĒ)
- BS = K(lnZ + βĒ)
- CS = lnZ + βĒ
- DNone of these
The particles whose spin angular momenta are (n + ½)ħ, where n = 0, 1, 2, 3, ..., are called
- Amesons
- Bphonons
- Cbosons
- Dfermions
The equilibrium number of photons in the radiation cavity is directly proportional to (Where V = Volume of cavity)
- AVT²
- BV/T³
- CVT³
- DV²T³
In simple random walk problem, the mean square deviation (Δn₁)² =
- A1/Npq
- BNpq
- Cn₁² − n₁ (mean values)
- D√(Npq)
Questions 131 – 135
The bisection method is guaranteed to converge if
- AThe derivative exists everywhere
- BThe function is linear
- CThe function has multiple roots
- DThe function is continuous and changes sign over the interval
The finite difference method is particularly suitable for
- ANon-linear algebraic equations only
- BProbability distributions
- CFourier series expansions
- DBoundary value problems involving differential equations
The truncation error of the trapezoidal rule is proportional to
- A1/n
- B1/n²
- C1/n³
- D1/n⁴
Which statement is true about the Poisson distribution?
- AIt is a continuous probability distribution.
- BIt models the number of events occurring in a fixed interval at a constant average rate.
- CIt requires fixed no. of trials.
- DThe mean and variance are different.
The probability distribution function of normal distribution is defined over the interval
- A0 ≤ x ≤ 1
- B−1 ≤ x ≤ 1
- C−∞ < x < ∞
- D0 < x < ∞
Questions 136 – 140
The mean deviation (D̄) in terms of deviations from the mean value of n reading is
- AΣd / n
- BΣ|d| / n
- C√(Σd²) / n
- D√(Σd² / n)
The heat generated by a linear IC-741 is 200 mw. If thermal resistance is 150° C/W and the ambient temperature is 25° C, then the device temperature is
- A40° C
- B45° C
- C50° C
- D55° C
Common Mode Rejection Ratio (CMRR) of a differential amplifier is given by (Ad → voltage gain of difference signal and Ac → voltage gain of common mode signal)
- Aρ = |Ad/Ac|
- Bρ = Ad/Ac
- Cρ = |Ac/Ad|
- Dρ = Ac/Ad
Basic instrumentation amplifier using three Op-Amp should have characteristics
- AHigh input impedance and low common mode rejection ratio
- BLow input impedance and low common mode rejection ratio
- CBoth input impedance and common mode rejection ratio high
- DLow input impedance and high common mode rejection ratio
For IC-741 Op-Amp following parameters are given. Quiescent collector current Ic = 9.5 μA, Cc = 30 PF, Peak amplitude of input voltage Vm = 1.5 V, so the slew rate is
- A0.23 V/μ sec.
- B0.43 V/μ sec.
- C0.63 V/μ sec.
- D0.73 V/μ sec.
Questions 141 – 145
Which of the following disintegration series of the heavy elements will give ²⁰⁹Bi as a stable nucleus?
- AThorium series
- BNeptunium series
- CUranium series
- DActinium series
Nuclear fusion required high temperature because
- AAll nuclear reactions absorb heat
- BThe particles cannot come closer unless they are moving rapidly
- CThe binding energy must be supplied from an external source
- DThe mass deficit must be supplied
The thermal ionization formula was proposed by
- AM.N. Saha
- BJ.C. Bose
- CHomi Bhabha
- DKepler
The reaction e⁺ + e⁻ → μ⁺ + π⁻ is forbidden because of
- ALaw of Baryon number conservation
- BLaw of momentum energy conservation
- CLaw of muon number conservation
- DNone of the above
Atomic mass of an element is 232 and its atomic number is 90. The end product of this radioactive element is an isotope of lead (atomic mass 208 and atomic number 82). The number of alpha and beta particles emitted as
- Aα = 6 and β = 0
- Bα = 6 and β = 4
- Cα = 4 and β = 6
- Dα = 3 and β = 3
Questions 146 – 150
The Hall coefficient (RH) is given by (Where symbols have their usual meaning)
- AEy / (JxH)
- BEx / (JyH)
- CEyH / Jx
- DExH / Jy
If the crystal is at constant pressure P, then the Gibbs free energy G is given by the relation
- AU + TS − PV
- BU − TS + PV
- CTS − U + PV
- DU − TS − PV
In Fermi energy-the transitional energy (Etrans) and momentum (Ptrans) are related by the expression (Where m is the mass of electron)
- AEtrans = (1/2m) Ptrans
- BEtrans = (1/m) Ptrans
- CEtrans = (1/m) P²trans
- DEtrans = (1/2m) P²trans
The kinetic energy (KE) for metals, where m* is an effective mass is given by the expression
- AKE = h²k² / 8π²m*
- BKE = h²k / 8π²m*
- CKE = hk² / 8π²m*
- DKE = h²k² / 4π²m*
The Pauli paramagnetic susceptibility (χ) is given by the expression (Where symbols have their usual meaning)
- Aχ = μB² g(εF)
- Bχ = μB g(εF)
- Cχ = μB g²(εF)
- Dχ = μB g(εF)²
Answer Key at a Glance (Q101–Q150)
| Q.No. | Answer | Correct Option |
|---|---|---|
| 101 | A | β = Δf / fm |
| 102 | D | 0.6 |
| 103 | B | Thermistors, thermocouples, RTDs |
| 104 | D | Photo-voltaic cell |
| 105 | D | y = 1.63x − 1.0809 |
| 106 | C | Do not obey superposition principle if dielectric permittivity (ε) depends on electric field (E) |
| 107 | D | 0.04 |
| 108 | C | 90° |
| 109 | A | TEM |
| 110 | D | π × 10¹¹ Hz |
| 111 | C | J₁² and J₂² commute with both J² and Jz |
| 112 | B | Discrete |
| 113 | D | [n(n+1)²] |n⟩ |
| 114 | B | Perturbed Hamiltonian from one stationary state to a group of states per unit time |
| 115 | A | En(1) = ⟨n(0)|V|n(0)⟩ |
| 116 | D | dqi/dt = ∂H/∂pi and −dpi/dt = ∂H/∂qi |
| 117 | B | 160 meter |
| 118 | C | (√3/2) C |
| 119 | C | v << c |
| 120 | A | m = h/λc |
| 121 | D | hν = Rhc (z−b)² [1/n₁² − 1/n₂²] |
| 122 | C | 8 × 10⁻²⁸ kg |
| 123 | C | A₂₁/B₂₁ ∝ ν³ |
| 124 | A | T = R(z−b)²/n² |
| 125 | A | O¹⁶ > Li⁷ (For both) |
| 126 | C | First |
| 127 | B | S = K(lnZ + βĒ) |
| 128 | D | fermions |
| 129 | C | VT³ |
| 130 | B | Npq |
| 131 | D | The function is continuous and changes sign over the interval |
| 132 | D | Boundary value problems involving differential equations |
| 133 | B | 1/n² |
| 134 | B | It models the number of events occurring in a fixed interval at a constant average rate. |
| 135 | C | −∞ < x < ∞ |
| 136 | B | Σ|d| / n |
| 137 | D | 55° C |
| 138 | A | ρ = |Ad/Ac| |
| 139 | C | Both input impedance and common mode rejection ratio high |
| 140 | C | 0.63 V/μ sec. |
| 141 | B | Neptunium series |
| 142 | B | The particles cannot come closer unless they are moving rapidly |
| 143 | A | M.N. Saha |
| 144 | C | Law of muon number conservation |
| 145 | B | α = 6 and β = 4 |
| 146 | A | Ey / (JxH) |
| 147 | B | U − TS + PV |
| 148 | D | Etrans = (1/2m) P²trans |
| 149 | A | KE = h²k² / 8π²m* |
| 150 | A | χ = μB² g(εF) |
The answers on this page have been collected and prepared with the help of Artificial Intelligence (AI). While we try to keep them accurate, errors or mistakes are possible. This is not an official MPPSC answer key. IrfanEdu.com does not take any responsibility for any wrong answer, correction or change, or for any decision made on the basis of this content.
For final and correct answers, always refer to the official answer key published on the MPPSC website. If you find any mistake, please let us know in the comments so we can correct it.
