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Question 1. Which statement best distinguishes a scientific law from a scientific theory? A) Laws explain phenomena, theories describe observations B) Laws are universally true, theories are provisional explanations C) Laws are hypotheses, theories are confirmed facts D) Laws are based on experiments, theories are purely speculative Answer: B Explanation: Scientific laws describe consistent and universal observations, while theories are well- substantiated explanations that may be revised with new evidence. Question 2. Empirical evidence in science refers to data obtained through: A) Logical deduction B) Theoretical modeling C) Observation and experimentation D) Philosophical reasoning Answer: C Explanation: Empirical evidence is gained through direct observation and experimentation, serving as the foundation for scientific conclusions. Question 3. Which characteristic best illustrates the iterative nature of scientific inquiry? A) Scientists wait for consensus before publishing findings B) Scientific hypotheses are tested, refined, or discarded based on new evidence C) Once a theory is established, it remains unchallenged D) Experiments are only performed once to confirm results Answer: B Explanation: Scientific inquiry is iterative because hypotheses and theories are continuously tested and refined as new evidence emerges. Question 4. When conducting scientific measurements, which SI unit is used for electric current? A) Volt B) Ohm
C) Ampere D) Watt Answer: C Explanation: The SI unit for electric current is the ampere (A). Question 5. Significant figures in a measurement are important because they: A) Indicate the exactness of the measurement B) Show the number of decimal places C) Are arbitrary and vary by scientist D) Only apply to digital instruments Answer: A Explanation: Significant figures reflect the precision of a measurement, indicating the digits that are reliably known. Question 6. Which type of graph is most suitable for showing the relationship between two continuous variables? A) Bar graph B) Pie chart C) Scatter plot D) Histogram Answer: C Explanation: Scatter plots are ideal for visualizing correlations and relationships between two continuous variables. Question 7. In an experiment, the independent variable is the one that: A) Is kept constant B) Is measured as the outcome C) Is manipulated to observe effects D) Is unrelated to the hypothesis Answer: C
A) Velocity B) Displacement C) Speed D) Force Answer: C Explanation: Speed is a scalar quantity, having only magnitude, whereas velocity and force are vectors. Question 12. A car accelerates from 20 m/s to 40 m/s over 10 seconds. Its average acceleration is: A) 2 m/s² B) 4 m/s² C) 0.5 m/s² D) 20 m/s² Answer: A Explanation: Average acceleration = (final velocity – initial velocity) / time = (40 – 20)/10 = 2 m/s². Question 13. In projectile motion, the horizontal component of velocity remains constant if: A) Air resistance is ignored B) Gravity acts on the projectile C) The projectile is at its peak height D) The projectile lands back on the ground Answer: A Answer: A Explanation: Without air resistance, the horizontal velocity remains constant since no net force acts horizontally. Question 14. Newton’s First Law states that an object will remain at rest or in uniform motion unless acted upon by: A) An external force B) Gravity
C) Friction D) A net force Answer: D Explanation: An object stays in its current state unless a net external force causes acceleration. Question 15. Which force opposes the motion of a sliding object? A) Normal force B) Frictional force C) Tension D) Gravitational force Answer: B Explanation: Friction opposes the relative motion between surfaces. Question 16. According to Newton’s Law of Universal Gravitation, the gravitational force between two masses depends on: A) The product of their masses and the distance squared between them B) Only their masses C) Their volumes and the distance between them D) The difference of their masses and the distance squared Answer: A Explanation: The law states that gravitational force ∝ (mass1 × mass2) / distance². Question 17. The work done on an object is positive when: A) The force opposes the displacement B) The force is perpendicular to the displacement C) The force and displacement are in the same direction D) The object is at rest Answer: C
B) Elastic collisions only C) Inelastic collisions only D) Isolated systems where no external force acts Answer: D Explanation: Momentum conservation applies in isolated systems with no external forces. Question 22. In an elastic collision, the total kinetic energy: A) Is conserved B) Is transformed into potential energy C) Is dissipated as heat D) Increases after the collision Answer: A Explanation: Elastic collisions conserve total kinetic energy and momentum. Question 23. Angular displacement measures: A) The linear distance traveled along a path B) The change in the angle of an object rotating about a point C) The speed of rotation D) The rate of change of linear velocity Answer: B Explanation: Angular displacement quantifies the change in angular position during rotation. Question 24. The moment of inertia depends on: A) The distribution of mass relative to the axis of rotation B) The total mass of the object only C) The angular velocity D) The external torque applied Answer: A Explanation: Moment of inertia depends on how mass is distributed around the axis of rotation.
Question 25. Simple harmonic motion (SHM) is characterized by: A) Uniform acceleration in one direction B) Oscillations with a restoring force proportional to displacement C) Motion with constant velocity D) Unpredictable and irregular oscillations Answer: B Explanation: SHM involves oscillations where the restoring force (and acceleration) is proportional to displacement, like a mass-spring system. Question 26. In a mass-spring system undergoing SHM, the period depends on: A) The mass and the spring constant only B) The amplitude of oscillation only C) The mass, spring constant, and amplitude D) The initial velocity of the mass Answer: A Explanation: The period T = 2π√(m/k) depends on mass m and spring constant k, not on amplitude. Question 27. Coulomb’s Law states that the electrostatic force between two point charges is directly proportional to: A) The product of the charges and inversely proportional to the square of the distance between them B) The sum of the charges C) The inverse of the charges and directly proportional to distance D) The difference of the charges and the distance Answer: A Explanation: Coulomb’s Law: F = k |q₁ q₂| / r², showing the force depends on the product of charges and inverse square of distance. Question 28. Which device stores electrical energy in an electric field? A) Resistor
Explanation: Moving charges or currents generate magnetic fields, as described by Ampère’s Law. Question 32. The force on a current-carrying wire placed in a magnetic field is maximum when: A) The wire is parallel to the magnetic field B) The wire is perpendicular to the magnetic field C) The wire is at an angle of 45° to the magnetic field D) The current is zero Answer: B Explanation: The magnetic force is maximized when the wire is perpendicular to the magnetic field. Question 33. Faraday’s Law states that a changing magnetic flux induces: A) An electric field B) An electric current in a conductor C) A magnetic monopole D) A static electric charge Answer: B Explanation: A changing magnetic flux induces an electromotive force (EMF), causing current in a conductor. Question 34. Which property of light explains the phenomenon of polarization? A) Its wave nature with oscillating electric and magnetic fields B) Its particle nature with photons C) Its ability to diffract around objects D) Its reflection from surfaces Answer: A Explanation: Polarization results from the wave nature of light, where the electric field oscillates in a specific plane. Question 35. The law of reflection states that the angle of incidence equals:
A) The angle of refraction B) The angle of reflection C) The angle of diffraction D) The angle of polarization Answer: B Explanation: The law of reflection states that the angle of incidence equals the angle of reflection, measured from the normal. Question 36. In a converging lens, the image formed by a distant object is: A) Real, inverted, and reduced in size B) Virtual, upright, and magnified C) Real, upright, and magnified D) Virtual, inverted, and reduced Answer: A Explanation: A converging lens forms a real, inverted, and reduced image of distant objects. Question 37. The phenomenon where two waves combine to produce a wave of greater amplitude is called: A) Diffraction B) Interference C) Reflection D) Polarization Answer: B Explanation: Interference involves the superposition of waves, resulting in constructive (greater amplitude) or destructive interference. Question 38. The photoelectric effect demonstrates that: A) Light behaves only as a wave B) Light can eject electrons from a metal surface only if its frequency exceeds a threshold C) Light energy depends on intensity alone
Question 42. The principle of superposition states that: A) Waves cancel each other out when they meet in phase B) The resultant wave is the algebraic sum of individual waves C) Waves cannot pass through each other D) Only waves of the same frequency can interfere Answer: B Explanation: Superposition means that when waves overlap, their displacements add algebraically to form the resultant wave. Question 43. In a diffraction experiment, the pattern observed is due to: A) Reflection of light waves B) Interference of light waves past an obstacle or slit C) Absorption of light by the medium D) Polarization of light waves Answer: B Explanation: Diffraction patterns result from the interference of waves passing through slits or around obstacles. Question 44. The Doppler effect causes the observed frequency of a wave to: A) Remain constant regardless of motion B) Increase when the source and observer move apart C) Shift higher when the source approaches the observer D) Shift lower when the source approaches the observer Answer: C Explanation: When the source approaches, the observed frequency increases; when it recedes, it decreases. Question 45. The index of refraction of a medium is defined as: A) The ratio of the speed of light in vacuum to that in the medium
B) The ratio of the speed of light in the medium to that in vacuum C) The ratio of the wavelength in vacuum to the wavelength in the medium D) The ratio of the frequency in vacuum to that in the medium Answer: A Explanation: The index of refraction n = c / v, where c is the speed of light in vacuum, and v is the speed in the medium. Question 46. A converging lens forms a real image when the object is located: A) Beyond 2F (twice the focal length) B) At 2F C) Between F and 2F D) Closer to the lens than F Answer: A Explanation: When an object is beyond 2F in a converging lens, the image is real, inverted, and reduced. Question 47. In the photoelectric effect, increasing the intensity of incident light: A) Increases the kinetic energy of ejected electrons B) Increases the number of ejected electrons but not their energy C) Has no effect on electron ejection D) Decreases the threshold frequency required for ejection Answer: B Explanation: Increasing intensity increases the number of ejected electrons but does not change their maximum kinetic energy, which depends on frequency. Question 48. The principle of relativity states that the laws of physics are the same in: A) All inertial frames of reference B) Only in frames at rest C) Only in frames moving at constant velocity D) Only in gravitational fields
A) A proton with an electron attached B) A helium nucleus consisting of two protons and two neutrons C) An electron emitted during beta decay D) A photon emitted during gamma decay Answer: B Explanation: Alpha particles are helium nuclei, composed of two protons and two neutrons. Question 53. The half-life of a radioactive isotope is: A) The time it takes for half of the nuclei to decay B) The time for the activity to double C) The time for all nuclei to decay D) The time it takes for the isotope to become stable Answer: A Explanation: Half-life is the period in which half of the radioactive nuclei decay. Question 54. The ideal gas law PV = nRT applies under which conditions? A) When gases behave ideally, with negligible interactions between molecules B) At extremely high pressures and low temperatures C) For liquids and solids at constant temperature D) Only for gases in a gravitational field Answer: A Explanation: The ideal gas law assumes negligible intermolecular forces and point-like molecules, valid under certain conditions. Question 55. According to Bernoulli’s principle, an increase in the speed of a fluid results in: A) An increase in pressure B) A decrease in pressure C) No change in pressure D) An increase in temperature only
Answer: B Explanation: Faster fluid flow leads to a pressure decrease in the flow region. Question 56. The concept of thermal expansion is observed because: A) Molecules move closer as temperature increases B) Molecules vibrate more vigorously, causing materials to expand C) Heat energy decreases material size D) Materials contract when heated Answer: B Explanation: Increased molecular vibrations cause materials to expand with rising temperature. Question 57. The second law of thermodynamics states that: A) Entropy of an isolated system always decreases B) Entropy of an isolated system tends to increase or stay the same C) Energy is conserved in all processes D) Heat can spontaneously flow from cold to hot objects Answer: B Explanation: Entropy tends to increase in isolated systems, indicating irreversibility. Question 58. In an adiabatic process, the system: A) Exchanges heat with surroundings B) Does not exchange heat with surroundings C) Has constant temperature D) Is in thermal equilibrium at all times Answer: B Explanation: An adiabatic process involves no heat transfer into or out of the system. Question 59. The phase diagram of water shows that at 0°C and 1 atm, water can exist as: A) Only solid
Question 63. Which property is conserved in a perfectly elastic collision? A) Total kinetic energy only B) Total momentum only C) Both total kinetic energy and total momentum D) Neither kinetic energy nor momentum Answer: C Explanation: Both kinetic energy and momentum are conserved in a perfectly elastic collision. Question 64. The angular velocity of an object in uniform circular motion is: A) The rate of change of angular displacement B) The linear velocity divided by radius C) The same as linear velocity D) The rate of change of linear speed Answer: A Explanation: Angular velocity is the rate of change of angular displacement over time. Question 65. The torque τ acting on a body is given by: A) τ = Force × Distance from pivot B) τ = Force / Distance C) τ = Force × Radius² D) τ = Force × Velocity Answer: A Explanation: Torque is the product of force and the lever arm distance perpendicular to the force. Question 66. The moment of inertia of a solid sphere about its center is proportional to: A) Its mass and radius squared B) Its mass only C) Its volume only
D) Its surface area Answer: A Explanation: Moment of inertia for a solid sphere is I = (2/5) m r². Question 67. The period of a simple pendulum depends primarily on: A) Its mass B) The length of the pendulum and acceleration due to gravity C) The amplitude of oscillation D) The initial push applied Answer: B Explanation: Period T = 2π√(L/g), depending on length L and gravity g. Question 68. The wave property responsible for sound traveling faster in solids than in gases is: A) Wavelength B) Wave speed depends on medium density and elasticity C) Frequency D) Amplitude Answer: B Explanation: Wave speed depends on the medium’s elasticity and density, higher in solids. Question 69. The speed of electromagnetic waves in vacuum is: A) Zero B) Equal to the speed of sound C) Approximately 3 × 10^8 m/s D) Dependent on wavelength Answer: C Explanation: Electromagnetic waves travel in vacuum at approximately 300 million meters per second.
