Q1.What does the ideal gas law state about the behavior of an ideal gas?
A.Pressure is inversely proportional to temperature
Pressure, volume, and temperature are related by PV = nRT
C.Volume is independent of temperature
D.Temperature is always constant
Explanation: The ideal gas law states that for an ideal gas, pressure (P), volume (V), and temperature (T) are related by PV = nRT, where n is the number of moles and R is the universal gas constant. This equation assumes ideal conditions with no intermolecular forces.
Q2.What is the main cause of tides on Earth?
A.Rotation of the Earth
Gravitational pull of the Moon
C.Solar radiation
D.Earth's magnetic field
Explanation: The gravitational pull of the Moon causes tides by exerting a force on Earth's oceans, creating high and low tides. The Sun also contributes, but the Moon’s effect is dominant due to its proximity.
Q3.What does the uncertainty principle state about a particle’s properties?
A.Position and momentum can be measured precisely simultaneously
There is a limit to the precision of knowing position and momentum simultaneously
C.Energy and time are always constant
D.Position is independent of momentum
Explanation: Heisenberg’s uncertainty principle states that there is a fundamental limit to the precision with which a particle’s position and momentum can be known simultaneously, expressed as Δx·Δp ≥ ħ/2, where ħ is the reduced Planck’s constant.
Q4.A 2 kg mass moves at 4 ms^-1. What is its kinetic energy?
A.8 J
16 J
C.24 J
D.32 J
Explanation: Kinetic energy is calculated as KE = (1/2)mv^2 = (1/2) * 2 * 4^2 = 1 * 16 = 16 J. Options A, C, and D result from incorrect calculations.
Q5.What does the law of conservation of charge state about electric charge in a closed system?
A.Charge can be created but not destroyed
B.Charge can be destroyed but not created
Total electric charge remains constant
D.Charge is always transferred out of a closed system
Explanation: The law of conservation of charge states that the total electric charge in a closed system remains constant; charge can neither be created nor destroyed, only transferred between objects.
Q6.Which device converts mechanical energy into electrical energy?
A.Motor
B.Transformer
Generator
D.Capacitor
Explanation: A generator converts mechanical energy into electrical energy via electromagnetic induction. Motors convert electrical to mechanical energy, transformers adjust voltage, and capacitors store charge.
Q7.What does the first law of thermodynamics state about a system’s internal energy?
A.Internal energy always decreases
Change in internal energy equals heat added minus work done by the system
C.Internal energy is always constant
D.Internal energy depends only on volume
Explanation: The first law of thermodynamics states that the change in internal energy (ΔU) of a system equals the heat added (Q) minus the work done by the system (W): ΔU = Q - W, reflecting energy conservation.
Q8.A wave travels at 20 ms^-1 with a frequency of 40 Hz. What is its wavelength?
A.0.25 m
0.50 m
C.0.75 m
D.1.00 m
Explanation: Wavelength is calculated as λ = v / f = 20 / 40 = 0.5 m. Options A, C, and D result from incorrect divisions.
Q9.What does the law of conservation of angular momentum state for a rotating system?
A.Angular momentum increases with time
Angular momentum remains constant if no external torque acts
C.Angular momentum decreases with time
D.Angular momentum is always zero
Explanation: The law of conservation of angular momentum states that a system’s angular momentum remains constant if no external torque acts, as seen in spinning objects like figure skaters pulling in their arms.
Q10.What type of lens is used in a magnifying glass?
A.Concave lens
Convex lens
C.Plane lens
D.Parabolic lens
Explanation: A magnifying glass uses a convex lens to converge light, forming a magnified virtual image when the object is inside the focal length. Concave lenses diverge light, and plane or parabolic lenses are not used for magnification.
Q11.What does the theory of relativity state about time dilation?
A.Time passes at the same rate for all observers
Time passes slower for a moving observer relative to a stationary one
C.Time passes faster for a moving observer
D.Time is independent of motion
Explanation: Einstein’s theory of relativity states that time dilation causes time to pass slower for an observer moving relative to a stationary observer, significant at relativistic speeds.
Q12.A 10 V battery is connected to two 5 Ω resistors in series. What is the total current?
1 A
B.2 A
C.3 A
D.4 A
Explanation: Total resistance R = 5 + 5 = 10 Ω. Current I = V / R = 10 / 10 = 1 A, per Ohm’s law. Other options miscalculate resistance or voltage.
Q13.What does the mass-energy equivalence state in the context of relativity?
A.Mass and energy are unrelated
Mass can be converted into energy and vice versa
C.Mass is always conserved, but energy is not
D.Energy is always conserved, but mass is not
Explanation: Einstein’s mass-energy equivalence (E = mc^2) states that mass can be converted into energy and vice versa, with total mass-energy conserved, as seen in nuclear reactions.
Q14.Which characteristic applies to a convex lens?
A.It always forms virtual images
B.It diverges light rays
It can form real and virtual images
D.It is thinner at the center
Explanation: A convex lens can form real images (object outside focal point) or virtual images (object inside focal point). It converges light, is thicker at the center, and does not diverge rays.
Q15.What does the law of conservation of linear momentum state for colliding objects?
A.Momentum before collision is less than after
Momentum before collision equals momentum after if no external forces act
C.Momentum before collision is greater than after
D.Momentum is not conserved during collisions
Explanation: The law of conservation of linear momentum states that the total momentum before a collision equals the total momentum after, if no external forces (e.g., friction) act, applicable in elastic and inelastic collisions.
Q16.A 0.2 kg ball is thrown vertically upwards at 10 ms^-1. What is the maximum height? (g = 10 ms^-2)
A.2.5 m
5.0 m
C.7.5 m
D.10.0 m
Explanation: At maximum height, final velocity v = 0. Using v^2 = u^2 - 2gh, 0 = 10^2 - 2 * 10 * h, so 100 = 20h, h = 5 m. Other options misapply the kinematic equation.
Q17.What does the law of electrostatic attraction state about the force between charges?
A.Like charges attract, unlike charges repel
Like charges repel, unlike charges attract
C.All charges attract each other
D.All charges repel each other
Explanation: Coulomb’s law states that like charges repel and unlike charges attract, with the force proportional to the product of charges and inversely proportional to the square of the distance between them.
Q18.What is the effect of a dielectric material between capacitor plates?
A.Decreases capacitance
Increases capacitance
C.No effect on capacitance
D.Reduces voltage across plates
Explanation: A dielectric increases capacitance by reducing the electric field between plates, allowing more charge storage. It does not inherently reduce voltage unless connected to a fixed voltage source.
Q19.What does the law of radioactive decay state about a radioactive substance?
A.Rate of decay is constant
Rate of decay is proportional to undecayed nuclei
C.Rate of decay increases with time
D.Rate of decay decreases with temperature
Explanation: The law of radioactive decay states that the rate of decay is proportional to the number of undecayed nuclei, leading to exponential decay described by dN/dt = -λN, where λ is the decay constant.
Q20.A radioactive sample has a half-life of 2 hours. Initial activity is 800 counts per minute. What is the activity after 6 hours?
100 counts per minute
B.200 counts per minute
C.300 counts per minute
D.400 counts per minute
Explanation: 6 hours = 3 half-lives (6 / 2). Activity halves each half-life: 800 → 400 → 200 → 100 counts per minute. Other options miscalculate the number of half-lives.
Q21.What does the de Broglie relationship state about particles?
A.Only light has wave properties
All matter has wave-like properties, wavelength inversely proportional to momentum
C.Particles have wave properties only at high speeds
D.Particles do not have wave-like properties
Explanation: The de Broglie hypothesis states that all matter exhibits wave-like properties, with wavelength λ = h/p, where h is Planck’s constant and p is momentum, applicable to particles like electrons.
Q22.Which particle is emitted during beta minus decay?
A.Proton
B.Neutron
Electron
D.Photon
Explanation: Beta minus decay emits an electron and an antineutrino as a neutron transforms into a proton. Protons and neutrons remain in the nucleus, and photons are emitted in gamma decay.
Q23.What does the law of conservation of mechanical energy state for systems with conservative forces?
A.Mechanical energy increases over time
Mechanical energy remains constant
C.Mechanical energy decreases over time
D.Mechanical energy is not conserved
Explanation: The law of conservation of mechanical energy states that in a system with only conservative forces (e.g., gravity), total mechanical energy (kinetic + potential) remains constant, assuming no energy losses.
Q24.A 1 kg mass is attached to a spring with a spring constant of 100 Nm^-1. What is the period of oscillation?
0.2π s
B.0.4π s
C.0.6π s
D.0.8π s
Explanation: Period T = 2π√(m/k) = 2π√(1/100) = 2π * 0.1 = 0.2π s. Other options result from incorrect application of the formula.
Q25.What does the law of thermal expansion state about materials when heated?
A.Materials contract when heated
Materials expand, expansion proportional to temperature change
C.Materials do not change size
D.Materials expand only if liquids
Explanation: The law of thermal expansion states that most materials expand when heated, with expansion proportional to the temperature change and the material’s coefficient of thermal expansion, except in rare cases like water at certain temperatures.
Q26.What is the primary source of Earth’s magnetic field?
A.Solar wind
Molten iron in the Earth’s core
C.Rotation of the Earth
D.Gravitational force
Explanation: Earth’s magnetic field is generated by the geodynamo effect, where the movement of molten iron and nickel in the outer core creates electric currents, producing a magnetic field.
Q27.What does Gauss’s law state in electrostatics?
A.Electric field lines can start and end anywhere
B.Electric field lines form closed loops
Net electric flux through a closed surface is proportional to enclosed charge
D.Electric field lines never cross
Explanation: Gauss’s law states that the net electric flux through a closed surface is proportional to the charge enclosed, given by Φ = q/ε_0, where ε_0 is the permittivity of free space.
Q28.A 5 μF capacitor is connected to a 10 V battery. What is the stored charge?
A.25 μC
50 μC
C.75 μC
D.100 μC
Explanation: Charge Q = CV = 5 x 10^-6 * 10 = 50 x 10^-6 C = 50 μC. Other options misapply the capacitance formula.
Q29.What does Kepler’s third law state about planetary motion?
A.Orbital period squared is inversely proportional to distance cubed
Orbital period squared is proportional to distance cubed
C.Orbital period is independent of distance
D.Orbits are always circular
Explanation: Kepler’s third law states that the square of a planet’s orbital period (T) is proportional to the cube of its average distance (r) from the Sun: T^2 ∝ r^3, applicable to elliptical orbits.
Q30.Which is NOT a fundamental force in nature?
A.Gravitational force
B.Electromagnetic force
Frictional force
D.Weak nuclear force
Explanation: Frictional force is a contact force, not fundamental. The four fundamental forces are gravitational, electromagnetic, strong nuclear, and weak nuclear, governing interactions at all scales.
Q31.A sound wave has a frequency of 400 Hz and speed of 320 ms^-1. What is its wavelength?
A.0.6 m
0.8 m
C.1.0 m
D.1.2 m
Explanation: Wavelength λ = v / f = 320 / 400 = 0.8 m. Other options result from incorrect calculations.
Q32.What does nuclear fission involve?
A heavy nucleus splits into lighter nuclei, releasing energy
B.Two light nuclei combine to form a heavier nucleus
C.A nucleus splits without releasing energy
D.A nucleus splits only when heated
Explanation: Nuclear fission involves a heavy nucleus (e.g., uranium-235) splitting into two lighter nuclei when struck by a neutron, releasing energy, used in nuclear reactors and weapons.
Q33.What is the main purpose of a fuse in an electrical circuit?
A.Increase voltage
Protect from overloading
C.Store electrical energy
D.Convert AC to DC
Explanation: A fuse protects a circuit by melting and breaking the circuit if the current exceeds a safe level, preventing damage or fire hazards.
Q34.What is the SI unit of electric current?
A.Volt
Ampere
C.Ohm
D.Watt
Explanation: The SI unit of electric current is the ampere (A), measuring the flow of electric charge. Volt measures potential difference, ohm measures resistance, and watt measures power.
Q35.What is the power dissipated in a 10 Ω resistor with a 2 A current?
A.20 W
40 W
C.60 W
D.80 W
Explanation: Power P = I^2R = 2^2 * 10 = 4 * 10 = 40 W. Other options misapply the power formula.
Q36.What type of mirror forms a virtual, upright image smaller than the object?
A.Plane mirror
B.Concave mirror
Convex mirror
D.Parabolic mirror
Explanation: A convex mirror always forms a virtual, upright, and diminished image, used in rear-view mirrors. Plane mirrors form same-size images, concave mirrors vary, and parabolic mirrors are specialized.
Q37.What is the frequency of a pendulum with a period of 0.5 s?
A.1 Hz
2 Hz
C.3 Hz
D.4 Hz
Explanation: Frequency f = 1/T = 1/0.5 = 2 Hz. Other options miscalculate the inverse of the period.
Q38.What phenomenon causes the sky to appear blue?
A.Reflection
B.Refraction
Scattering
D.Diffraction
Explanation: Rayleigh scattering causes shorter blue wavelengths of sunlight to scatter more in the atmosphere, making the sky appear blue. Other processes do not explain this effect.
Q39.What is the work done by a 10 N force moving an object 5 m in the direction of the force?
A.25 J
50 J
C.75 J
D.100 J
Explanation: Work W = F * d * cosθ = 10 * 5 * cos(0) = 50 J, as the force and displacement are in the same direction. Other options misapply the formula.
Q40.What is the primary function of a transformer?
A.Convert DC to AC
B.Store electrical energy
Change voltage levels in AC circuits
D.Increase current in DC circuits
Explanation: A transformer changes voltage levels in AC circuits by electromagnetic induction, stepping up or down voltage. It does not work with DC, store energy, or convert DC to AC.