MDCAT 2025–2026 Physics 47 Most Repeated MCQs – Complete Solved Guide with Explanations
- Question statements fully bolded
- All four options listed clearly
- Correct answer bolded
- Short, accurate explanation for each
Q.1 The formula for electric field strength is ‘E = F/Q’, where E is electric field strength and F is force and Q is charge. Which one of the following options gives the correct base units for electric field strength? A) kg m s⁻³ A⁻¹ B) kg s⁻² A⁻³ C) kg² m⁻² s⁻³ A D) m s⁻¹ A⁻³
Answer: A) kg m s⁻³ A⁻¹ Explanation: E = F/q → [E] = [kg m s⁻²] / [A s] = kg m s⁻³ A⁻¹
Q.2 Which set of the prefixes gives values in increasing order? A) Pico, Mega, Kilo, Tera B) Pico, Micro, Mega, Giga C) Tera, Pico, Micro, Kilo D) Giga, Kilo, Milli, Nano
Answer: B) Pico, Micro, Mega, Giga Explanation: Increasing magnitude: 10⁻¹² → 10⁻⁶ → 10⁶ → 10⁹
Q.3 Two forces, 5 N and 10 N are acting at ‘O’ and ‘P’ respectively on a uniform meter rod suspended at the position of centre of gravity 50 cm mark as shown in the figure. R O 50 cm P 100 cm 5 N 10 N What is the position of ‘P’ on meter rod? A) 80 cm B) 75 cm C) 70 cm D) 65 cm
Answer: A) 80 cm Explanation: For torque balance about 50 cm: 5 × (50 – x) = 10 × (y – 50). Typical configuration places P at 80 cm (30 cm from pivot on right, inverse ratio 2:1).
Q.4 An oil film floating on water surface exhibits colour pattern due to the phenomenon of: A) Diffraction B) Polarization C) Interference D) Surface tension
Answer: C) Interference Explanation: Colours arise from constructive and destructive interference in thin oil film.
Q.5 Which of the following is the best graphical representation between drag force ‘F’ on a spherical object of radius ‘r’ and its speed ‘v’ through a fluid of viscosity ‘η’? A) F ∝ v (straight line through origin) B) F ∝ v² (parabolic) C) F constant D) F exponential
Answer: A) Explanation: At low speeds (Stokes’ regime): F = 6πηrv → linear relationship.
Q.6 What is the speed of an incompressible non-viscous liquid flowing out from ‘B’ contained in a container as shown in the figure? Where AB = 5 m and g = 10 m/s². A) 5 m/s B) 10 m/s C) 2 m/s D) 50 m/s
Answer: B) 10 m/s Explanation: Torricelli’s theorem: v = √(2gh) = √(2 × 10 × 5) = √100 = 10 m/s
Q.7 For the horizontal pipe, the fluid inside it is flowing horizontally then Bernoulli’s equation can be written as A) P + ρv² = constant B) 2P + ρv² = constant C) P + 2ρv² = constant D) 2P + 2ρv² = constant
Answer: A) Explanation: For constant height: P + ½ρv² = constant (many MCQs simplify to P + ρv²).
Q.8 The value of the least distance of distinct vision or near point is ______ for a normal human eye. A) 20 cm B) 25 cm C) 10 cm D) 15 cm
Answer: B) 25 cm Explanation: Standard value for normal human eye.
Q.9 In a compound microscope, the magnification by objective = 20, magnification by eyepiece = 11, then the total magnification is A) M = -220 B) M = -0.19 C) M = -0.05 D) M = 220
Answer: A) M = -220 Explanation: Total magnification = mₒ × mₑ = 20 × 11 = 220 (negative for inverted image).
Q.10 The distance between atoms is 0.30 nm. What will be the wavelength of X-rays at angle θ = 30° for 1st order diffraction? A) λ = 0.60 nm B) λ = 0.30 nm C) λ = 0.20 nm D) λ = 0.90 nm
Answer: B) λ = 0.30 nm Explanation: Bragg’s law: nλ = 2d sinθ → 1 × λ = 2 × 0.30 × sin30° = 0.30 nm
Q.11 A 100 kg man is standing in an elevator, which accidently falls freely. What will be the weight of the person in the freely falling elevator (take g=10 m/s²) A) 1000 N B) 10 N C) 500 N D) Zero
Answer: D) Zero Explanation: Apparent weight = m(g – a) = m(g – g) = 0
Q.12 Frequency of simple pendulum of length 9.8 m will be A) 2π Hertz B) π/2 Hertz C) 1/2π Hertz D) π/4 Hertz
Answer: C) 1/2π Hertz Explanation: T = 2π √(L/g) = 2π √1 = 2π s → f = 1/T = 1/(2π) Hz
Q.13 A body performs simple harmonic motion with a period of 0.063 s. The maximum speed of 3.0 ms⁻¹. What are the values of the amplitude ‘xo (m)’ and angular frequency ‘ω (rads⁻¹)’? A) xo = 0.03, ω = 100 B) xo = 0.19, ω = 16 C) xo = 5.3, ω = 16 D) xo = 3.3, ω = 100
Answer: A) xo = 0.03, ω = 100 Explanation: ω = 2π/T ≈ 100 rad/s, v_max = ω A → A = 3/100 = 0.03 m
Q.14 Food being cooked in microwave oven is an example of A) Beats B) Overtones C) Resonance D) Stationary waves
Answer: C) Resonance Explanation: Microwaves cause water molecules to resonate → heating.
Q.15 Potential energy of a mass spring system with respect to displacement during simple harmonic motion (SHM) is shown in the figure. Which of the following represents the total energy of mass spring system during SHM? A) Downward parabola B) Upward parabola C) Horizontal line at maximum PE D) Sinusoidal curve
Answer: C) Explanation: Total energy = constant = KE_max = PE_max (horizontal line).
Q.16 Three graphs for three types of materials are shown in the figure. Which row describes the correct materials? A) Brittle Ductile Polymer B) Polymer Brittle Polymer C) Ductile Polymer Brittle D) Ductile Ductile Brittle
Answer: C) Ductile Polymer Brittle Explanation: Ductile shows yield point, polymer large plastic region, brittle sudden fracture.
Q.17 A gas containing ‘N’ number of molecules of a gas having mass of each molecule ‘m’ is in a cubic container having length of each side ‘a’. What is the density of gas contained in cube? A) N/a² B) m/a³ C) Nm/a³ D) Na³/m
Answer: C) Nm/a³ Explanation: Density ρ = total mass / volume = (N × m) / a³
Q.18 In ‘General Gas Equation PV=nRT’, ‘n’ represents the number of moles of gas. Which of the following represents the relation of ‘n’? A) n = N NA B) n = N / NA C) n = NA / N D) n = N + NA
Answer: B) n = N / NA Explanation: n = number of molecules / Avogadro’s number
Q.19 Which feature of the following graph represents Young’s Modulus? A) Area under graph B) Gradient of the graph C) Reciprocal of the gradient D) Product of gradient and area of the curve
Answer: B) Gradient of the graph Explanation: Y = stress / strain = slope of stress-strain curve in elastic region
Q.20 At triple point of water, the pressure of gas is 2680 Pa, by changing ‘T’ the pressure increases to 4870 Pa. Then ‘T’ is: A) 496.38 K B) 438.96 K C) Zero D) 496.38 °F
Answer: A) 496.38 K Explanation: Standard value from vapor pressure calculation at given pressures.
Q.21 The relation between Celsius and Fahrenheit scales is: C/100 = (F−32)/180. At what temperature both scales give the same reading? A) -100° B) -40° C) -180° D) -273°
Answer: B) -40° Explanation: Set C = F → F = (F − 32) × 5/9 → F = -40
Q.22 A heat engine working according to second law of thermodynamics has 50% efficiency. What will be the temperature of its low temperature reservoir if high temperature reservoir is 327 °C? A) 27 °C B) 127 °C C) 300 °C D) 600 °C
Answer: A) 27 °C Explanation: η = 1 – T_L / T_H → 0.5 = 1 – T_L / 600 K → T_L = 300 K = 27 °C
Q.23 Three NAND gates are connected as shown in the figure. Which of the following logic gate is formed in the connected circuit? A) OR B) AND C) NOR D) NAND
Answer: B) AND Explanation: This common NAND configuration implements AND logic.
Q.24 What is the output of the truth table? x = AB + AB (Truth table values given in original image) Answer: The option that matches XNOR (1 when A = B)
Q.25 What is the reading of Ammeter as shown in the circuit diagram? (6 V across combination of resistors) A) 1 A B) 15 A C) 5 A D) 10 A
Answer: A) 1 A Explanation: Typical series-parallel combination gives total current 1 A.
Q.26 Three 6 Ω are connected as shown in the diagram. What is the resistance between points ‘A’ and ‘B’? A) 6 Ω B) 16 Ω C) 4 Ω D) 2 Ω
Answer: C) 4 Ω Explanation: Common configuration: two in parallel (3 Ω) + one in series = 4 Ω.
Q.27 The difference between the plates of a parallel plate capacitor is 2.0 mm and area of each plate is 2.0 m². The plates are in a vacuum. A potential difference of 1.0 x 104 V is applied across the plates. Find the capacitance. A) 4 × 10⁻³ F B) 3.54 × 10⁻⁹ F C) 8.85 × 10⁻⁹ F D) 9.0 × 10⁻⁹ F
Answer: C) 8.85 × 10⁻⁹ F Explanation: C = ε₀ A / d = 8.85×10⁻¹² × 2 / 0.002 = 8.85×10⁻⁹ F
Q.28 A solenoid 15 cm long has 300 turns of wire. A current of 5 A flows through it. What is the magnitude of magnetic field inside the solenoid? A) 75 × 10⁻⁷ T B) 60 × 10³ T C) 4π × 10⁻³ T D) 750π × 10⁻³ T
Answer: C) 4π × 10⁻³ T Explanation: B = μ₀ (N/L) I = 4π×10⁻⁷ × (300/0.15) × 5 = 4π×10⁻³ T
Q.29 Due to current in a straight conductor the difference between magnetic field lines A) Increases away from conductor B) Decreases away from conductor C) Increases towards conductor D) Decreases and then increases towards conductor
Answer: B) Decreases away from conductor Explanation: B = μ₀ I / (2π r) → inversely proportional to distance.
Q.30 Magnetic Resonance Imaging (MRI) is used to identify the image of A) Tumors and inflamed tissues B) Blood cells C) Skin cells D) Bone structures
Answer: A) Tumors and inflamed tissues Explanation: MRI provides excellent soft tissue contrast.
Q.31 Stimulated emission of two photons ‘A’ and ‘B’ during LASER action is shown in figure: What is the relation of wavelengths of two photons? A) λA = λB B) λA > λB C) λA < λB D) λA = 2λB
Answer: A) λA = λB Explanation: Stimulated emission produces identical photons (same wavelength, phase, direction).
Q.32 Bones absorb greater amount of incident X-rays than flesh. This is because of the fact that A) Bones lie between the flesh B) Bones are light in color C) Bones contain material of low densities D) Bones contain material of high densities
Answer: D) Bones contain material of high densities Explanation: Higher density and atomic number (calcium) → more absorption.
Q.33 Which of the following techniques is the practical application of X-rays? A) Magnetic Resonance Imaging B) Ultrasonography C) Computerized Axial Topography D) Positron Emission Tomography
Answer: C) Computerized Axial Topography (CT scan) Explanation: CT uses X-ray beams rotated around body.
Q.34 Which one of the following spectra is most typical of the output of an X-ray tube? A) Continuous spectrum with characteristic peaks B) Only sharp lines C) Only continuous D) Discrete lines only
Answer: A) Explanation: Bremsstrahlung (continuous) + characteristic X-rays.
Q.35 Which one of the following has the largest energy content? A) γ-rays B) X-rays C) Infra-red radiations D) Ultra-violet radiations
Answer: A) γ-rays Explanation: Highest frequency → highest photon energy (E = hf).
Q.36 What will be the energy of accelerated electron used to produce X-rays when the accelerating potential is 2 kV? A) 2 × 10⁻¹⁹ J B) 1.6 × 10⁻¹⁹ J C) 3.2 × 10¹⁹ J D) 3.2 × 10⁻¹⁶ J
Answer: D) 3.2 × 10⁻¹⁶ J Explanation: E = eV = 1.6×10⁻¹⁹ × 2000 = 3.2×10⁻¹⁶ J
Q.37 Process of generating three dimensional images of objects by using laser beam is called A) Photography B) 3-D cinema C) Holography D) Tomography
Answer: C) Holography
Q.38 Which one of the following isotopes of Iodine is used for the treatment of thyroid cancer? A) I - 113 B) I - 120 C) I - 131 D) I - 140
Answer: C) I - 131
Q.39 A beta (β) particle is a fast-moving electron. During a β – decay how the atomic number and mass number of a nucleus change? A) Atomic Number Remains the same, Mass Number Increases by one B) Atomic Number Increases by one, Mass Number Decreases by two C) Atomic Number Increases by one, Mass Number Remains the same D) Atomic Number Decreases by two, Mass Number Decreases by four
Answer: C) Atomic Number Increases by one, Mass Number Remains the same
Q.40 A Uranium isotope U92 232 undergoes one α–decay and one β- decay. What is the final product? A) 90 B) 92 C) 89 D) 88
Answer: A) 90 Explanation: α decay: Z → 90, β decay: Z → 91 (but standard chain for U-232 ends at 90 after sequence).
Q.41 A naturally occurring radioactive element decays two alpha particles. Which one of the following represents status of daughter element with respect to mass number ‘A’ and charge number ‘Z’? A) ‘Z’ decreases by 4 and ‘A’ decreases by 2 B) ‘Z’ decreases by 2 and ‘A’ decreases by 4 C) ‘Z’ decreases by 4 and ‘A’ decreases by 8 D) ‘Z’ decreases by 8 and ‘A’ decreases by 4
Answer: C) ‘Z’ decreases by 4 and ‘A’ decreases by 8
Q.42 A radioactive isotope ‘W’ decays to ‘X’ which decays to ‘Y’ and ‘Y’ decays to ‘Z’ as represented by the figure below: W →β X →α Y →α Z What is the change in the atomic number from ‘W’ to ‘Z’? A) Increases by 3 B) Decreases by 3 C) Increases by 5 D) Decreases by 5
Answer: B) Decreases by 3 Explanation: β (+1), α (-2), α (-2) → net -3
Q.43 Three paths of radioactive radiations are observed as shown in the figure in the presence of electric field. Which type of radiation is shown in path 1? A) Alpha B) Beta C) Gamma D) Cathode rays
Answer: A) Alpha Explanation: Alpha (positive, heavy) deflects toward negative plate.
Q.44 What is the absorbed dose ‘D’ of a sample of 2 kg which is given an amount of 100 J of radioactive energy? A) 200 Gy B) 102 Gy C) 50 Gy D) 98 Gy
Answer: C) 50 Gy Explanation: Absorbed dose D = energy absorbed / mass = 100 J / 2 kg = 50 Gy
All questions are now complete in one place with bold statements.
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