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Question 1. Which of the following best defines accuracy in a measurement? A) The closeness of repeated measurements to each other. B) The closeness of a measurement to the true value. C) The number of significant figures reported. D) The range of possible values. Answer: B Explanation: Accuracy refers to how near a measured value is to the accepted true value. Question 2. In vector addition, the resultant of two perpendicular vectors of equal magnitude is: A) Same magnitude as each vector. B) √2 times the magnitude of each vector. C) Twice the magnitude of each vector. D) Zero. Answer: B Explanation: Using the Pythagorean theorem, the resultant magnitude is √(A²+A²)=√2 A. Question 3. The slope of a distance-time graph represents: A) Acceleration. B) Velocity. C) Displacement. D) Force. Answer: B Explanation: Slope = Δdistance/Δtime = average velocity. Question 4. A projectile is launched at 30° above the horizontal with speed v₀. Its horizontal range is proportional to: A) v₀² sin 30°. B) v₀² sin 60°. C) v₀ cos 30°. D) v₀ sin 30°.
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Answer: B Explanation: Range = (v₀² sin 2θ)/g; for θ=30°, sin 60° appears. Question 5. Newton’s first law is a statement of: A) Conservation of energy. B) Inertia of a body at rest or uniform motion. C) Action-reaction pairs. D) Relationship between force and acceleration. Answer: B Explanation: The law says a body remains at rest or moves uniformly unless acted on by a net force. Question 6. If a net external force of 10 N acts on a 2 kg mass, its acceleration is: A) 0.2 m/s². B) 5 m/s². C) 20 m/s². D) 12 m/s². Answer: B Explanation: a = F/m = 10 N/2 kg = 5 m/s². Question 7. According to Newton’s third law, the force that a book exerts on a table is: A) Greater than the force the table exerts on the book. B) Equal in magnitude and opposite in direction to the force the table exerts on the book. C) Zero because the book is at rest. D) Dependent on the book’s mass. Answer: B Explanation: Action-reaction forces are equal and opposite. Question 8. Work done by a constant force that is perpendicular to the displacement is:
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Question 12. A perfectly elastic collision between two identical balls results in: A) Both balls stopping. B) The first ball stops, the second moves with original speed. C) Both balls moving together. D) No change in velocities. Answer: B Explanation: In a 1-D elastic collision of equal masses, the moving ball stops and transfers its speed to the stationary one. Question 13. Centripetal acceleration for an object moving in a circle of radius r with speed v is: A) v²/r. B) r²/v. C) v/r². D) r/v. Answer: A Explanation: a_c = v²/r directed toward the center. Question 14. The gravitational force between two 1 kg masses separated by 1 m is approximately: A) 6.7×10⁻¹¹ N. B) 9.8 N. C) 1 N. D) 0 N. Answer: A Explanation: F = G m₁m₂/r²; G ≈ 6.67×10⁻¹¹ N·m²/kg². Question 15. Kepler’s third law states that the square of a planet’s orbital period is proportional to: A) The cube of its orbital radius. B) Its orbital radius. C) The square of its orbital radius.
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D) The cube of its orbital speed. Answer: A Explanation: T² ∝ r³ for planetary orbits. Question 16. The moment of inertia of a solid cylinder rotating about its central axis is: A) (1/2) MR². B) (1/12) ML². C) (2/5) MR². D) MR². Answer: A Explanation: I = ½ MR² for a solid cylinder about its symmetry axis. Question 17. Torque is the cross product of: A) Force and displacement. B) Force and lever arm. C) Momentum and radius. D) Velocity and acceleration. Answer: B Explanation: τ = r × F, magnitude = rF sin θ. Question 18. Coulomb’s law states that the electric force between two point charges varies as: A) The product of the charges and the square of the distance. B) The product of the charges divided by the square of the distance. C) The sum of the charges divided by the distance. D) The difference of the charges times distance. Answer: B Explanation: F = k q₁q₂/r². Question 19. The electric field at a point 0.10 m from a charge of +5 μC is: A) 4.5×10⁴ N/C.
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D) 2 Ω.
Answer: A Explanation: Series resistances add: 2+4+6 = 12 Ω. Question 23. Kirchhoff’s junction rule states that: A) The sum of potential differences in a closed loop is zero. B) The algebraic sum of currents entering a node is zero. C) Voltage equals current times resistance. D) Power is conserved in a circuit. Answer: B Explanation: At any junction, total entering current equals total leaving current. Question 24. The magnetic field at the center of a circular loop of radius R carrying current I is: A) μ₀I/2R. B) μ₀I/4πR. C) μ₀I/2πR. D) μ₀I/πR. Answer: C Explanation: B = μ₀I/2R for a single loop; using μ₀/4π factor gives μ₀I/2πR. Question 25. The force on a charge q moving with velocity v perpendicular to a magnetic field B is: A) qvB. B) qv/B. C) qB/v. D) 0. Answer: A Explanation: Lorentz force magnitude F = qvB sin 90° = qvB. Question 26. Faraday’s law of induction states that the induced emf in a coil equals:
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A) The rate of change of magnetic flux times the number of turns. B) The magnetic flux itself. C) The product of magnetic field and area. D) The resistance of the coil. Answer: A Explanation: ε = -N dΦ/dt. Question 27. According to Lenz’s law, the direction of an induced current is such that: A) It enhances the change in magnetic flux. B) It opposes the change in magnetic flux. C) It is always clockwise. D) It creates a magnetic field of zero magnitude. Answer: B Explanation: The induced emf acts to oppose the cause producing it. Question 28. The speed of a wave on a stretched string is given by v = √(T/μ). What does μ represent? A) Linear mass density. B) Magnetic permeability. C) Coefficient of friction. D) Elastic modulus. Answer: A Explanation: μ is mass per unit length of the string. Question 29. The frequency of a wave is 500 Hz and its wavelength is 0.68 m. Its speed is: A) 340 m/s. B) 0.00136 m/s. C) 850 m/s. D) 0.5 m/s. Answer: A
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B) 61°.
C) 90°.
D) 30°.
Answer: A Explanation: sinθc = n₂/n₁ = 1/1.33 → θc ≈ 48°. Question 34. The Doppler shift for a source moving toward a stationary observer results in: A) Lower frequency. B) Higher frequency. C) No change in frequency. D) Frequency becomes zero. Answer: B Explanation: Approaching source compresses wavefronts, increasing observed frequency. Question 35. The speed of sound in air at 20 °C is approximately: A) 340 m/s. B) 1500 m/s. C) 30 m/s. D) 1000 m/s. Answer: A Explanation: At room temperature, sound travels about 340 m/s in air. Question 36. The fundamental frequency of an open-open pipe of length L is given by: A) v/2L. B) v/L. C) v/4L. D) 2v/L. Answer: A Explanation: For both ends open, λ₁ = 2L, so f₁ = v/λ₁ = v/2L.
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Question 37. In a thermodynamic system, the quantity that remains constant during an isochoric process is: A) Pressure. B) Volume. C) Temperature. D) Internal energy. Answer: B Explanation: Isochoric means constant volume. Question 38. The first law of thermodynamics is a statement of: A) Conservation of momentum. B) Conservation of energy. C) Increase of entropy. D) Zero net work. Answer: B Explanation: ΔU = Q – W expresses energy conservation for a system. Question 39. The efficiency of an ideal Carnot engine operating between 500 K and 300 K is: A) 40%. B) 60%. C) 20%. D) 0%. Answer: A Explanation: η = 1 – Tc/Th = 1 – 300/500 = 0.40 = 40%. Question 40. The specific heat capacity of water is approximately: A) 0.5 J/g·K. B) 1.0 J/g·K. C) 4.2 J/g·K. D) 9.8 J/g·K.
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B) Temperature, entropy, and volume. C) Mass, charge, and magnetic field. D) Frequency, wavelength, and amplitude. Answer: A Explanation: Bernoulli’s principle: P + ½ρv² + ρgh = constant. Question 45. In an ideal gas, the internal energy depends only on: A) Pressure. B) Volume. C) Temperature. D) Number of moles. Answer: C Explanation: For ideal gases, U = f(T) only. Question 46. The Bohr model correctly predicts the wavelength of the spectral line emitted when an electron drops from n=3 to n=2 in hydrogen. This wavelength is in the: A) Infrared region. B) Visible region. C) Ultraviolet region. D) X-ray region. Answer: B Explanation: The Balmer series (n=2 to higher) lies in the visible spectrum; transition 3→2 is H-α (≈ 656 nm). Question 47. Planck’s constant (h) has units of: A) J·s. B) N·m. C) C·V. D) kg·m²/s³. Answer: A Explanation: h relates energy (J) to frequency (s⁻¹): E = hf, so units J·s.
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Question 48. In the photoelectric effect, increasing the intensity of incident light (while keeping frequency constant) results in: A) Higher kinetic energy of emitted electrons. B) More electrons emitted per unit time. C) No electrons emitted if frequency is below threshold. D) Both B and C. Answer: D Explanation: Intensity changes number of photons; if frequency is below threshold, no emission regardless of intensity. Question 49. The de Broglie wavelength of a neutron moving at 2000 m/s is approximately: A) 2 pm. B) 0.2 nm. C) 2 nm. D) 20 nm. Answer: B Explanation: λ = h/mv; neutron mass ≈ 1.675×10⁻²⁷ kg, h = 6.626×10⁻³⁴ J·s → λ ≈ 2.0×10⁻¹⁰ m = 0.2 nm. Question 50. The half-life of a radioactive isotope is 10 years. After 30 years, the fraction of the original sample remaining is: A) 1/2. B) 1/4. C) 1/8. D) 1/10. Answer: C Explanation: After three half-lives (3× 10 yr), remaining = (1/2)³ = 1/8. Question 51. In nuclear fission, the total mass of the products is: A) Greater than the original nucleus. B) Equal to the original nucleus.
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Question 55. The principle of superposition states that: A) Forces add vectorially. B) Energy is conserved. C) Waves interfere without affecting each other’s propagation. D) Both A and C. Answer: D Explanation: Superposition applies to forces and wave amplitudes. Question 56. In a double-slit experiment, the fringe spacing increases when the screen distance is: A) Decreased. B) Increased. C) Kept constant. D) Made zero. Answer: B Explanation: Fringe spacing Δy = λL/d; larger L yields larger spacing. Question 57. The refractive index of a medium is defined as: A) Speed of light in vacuum divided by speed in the medium. B) Speed in the medium divided by speed in vacuum. C) Ratio of frequencies. D) Ratio of wavelengths. Answer: A Explanation: n = c/v_medium. Question 58. A lens with focal length +20 cm is: A) Concave. B) Convex. C) Plano-convex. D) Plano-concave. Answer: B Explanation: Positive focal length indicates a converging (convex) lens.
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Question 59. The energy of a photon with wavelength 500 nm is: A) 2.5×10⁻¹⁹ J. B) 4.0×10⁻¹⁹ J. C) 6.6×10⁻¹⁹ J. D) 1.2×10⁻¹⁸ J. Answer: B Explanation: E = hc/λ = (6.626×10⁻³⁴)(3×10⁸)/5×10⁻⁷ ≈ 3.97×10⁻¹⁹ J ≈ 4.0×10⁻¹⁹ J. Question 60. In a simple harmonic oscillator, the restoring force is proportional to: A) Velocity. B) Displacement. C) Acceleration. D) Time. Answer: B Explanation: Hooke’s law: F = –kx. Question 61. The period of a mass-spring system depends on: A) Mass only. B) Spring constant only. C) Both mass and spring constant. D) Amplitude. Answer: C Explanation: T = 2π√(m/k); independent of amplitude. Question 62. The angular frequency ω of a pendulum of length L (small angles) is: A) √(g/L). B) √(L/g). C) g/L.
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A) Constant. B) Proportional to r. C) Inversely proportional to r². D) Zero. Answer: B Explanation: For r < R, E = (ρ r)/(3ε₀), so E ∝ r. Question 67. The magnetic field at a distance r from a long straight wire carrying current I is: A) μ₀I/2πr. B) μ₀I/4πr². C) μ₀I r/2π. D) μ₀I r²/4π. Answer: A Explanation: B = μ₀I/2πr from Ampère’s law. Question 68. In a transformer, the ratio of primary to secondary voltages equals the ratio of: A) Turns (Np/Ns). B) Currents (Ip/Is). C) Resistances. D) Power. Answer: A Explanation: Vp/Vs = Np/Ns. Question 69. The work function of a metal is 2.0 eV. Light of wavelength 400 nm shines on it. Will electrons be emitted? A) Yes, because photon energy > work function. B) No, because photon energy < work function. C) Yes, but only if intensity is high. D) No, because wavelength is too long. Answer: A
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Explanation: Photon energy E = hc/λ ≈ 3.1 eV > 2.0 eV, so emission occurs. Question 70. The rms speed of molecules in an ideal gas is proportional to: A) √(T). B) T. C) 1/√(T). D) √(1/T). Answer: A Explanation: v_rms = √(3kT/m). Question 71. A gas expands adiabatically, doing work on its surroundings. Its internal energy: A) Increases. B) Decreases. C) Remains constant. D) Becomes zero. Answer: B Explanation: No heat exchange (Q=0); ΔU = –W, so internal energy drops. Question 72. The speed of light in a medium of refractive index 1.33 is: A) 2.25×10⁸ m/s. B) 3.00×10⁸ m/s. C) 4.00×10⁸ m/s. D) 1.00×10⁸ m/s. Answer: A Explanation: v = c/n = 3.00×10⁸/1.33 ≈ 2.25×10⁸ m/s. Question 73. In a vacuum, the relationship between electric field amplitude E₀ and magnetic field amplitude B₀ of an electromagnetic wave is: A) E₀ = c B₀. B) E₀ = B₀/c. C) E₀ = B₀.
