A 1:4
B 1:16
C 4:1
D 16:1
Explanation: E₄/E₂ = (1/4²)/(1/2²) = (1/16)/(1/4) = 4/16 = 1/4. So E₄:E₂ = 1:4
A Electromagnetic
B Strongest but short range
C Gravitational
D Long range
Explanation: Nuclear force is the strongest force in nature but operates only over very short range (~10⁻¹⁵ m).
A Same atomic number
B Different atomic number
C Same mass number
D Same number of protons and neutrons
Explanation: In radioactive decay, the daughter nucleus has a different atomic number (and often different mass number) than the parent.
A Photoelectric effect
B Fine structure of spectral lines
C Blackbody radiation
D Compton effect
Explanation: Electron spin was introduced to explain the fine structure of spectral lines and the anomalous Zeeman effect.
A No two electrons can have same energy
B No two electrons can have same set of quantum numbers
C All electrons have same spin
D Only two electrons can exist in an atom
Explanation: Pauli exclusion principle: no two electrons in an atom can have identical values of all four quantum numbers.
A Position and momentum can be measured exactly
B The product of uncertainties in position and momentum has a minimum value
C Energy cannot be measured
D Time is absolute
Explanation: Δx · Δp ≥ h/4π. Position and momentum cannot both be known with arbitrary precision simultaneously.
A Energy of particle
B Probability density of finding the particle
C Momentum of particle
D Velocity of particle
Explanation: |ψ|² gives the probability density, meaning the probability of finding the particle at a given location.
A 10 Ω
B 20 Ω
C 30 Ω
D 40 Ω
Explanation: P/Q = R/S → 10/20 = 15/S → S = 30 Ω
A Tesla
B Weber
C Henry
D Gauss
Explanation: Magnetic flux Φ = B·A, SI unit is Weber (Wb) = T·m²
A Currents are in same direction
B Currents are in opposite direction
C One current is zero
D Conductors are perpendicular
Explanation: Parallel currents attract and anti-parallel currents repel each other.
A Magnetic field only
B Electric field only
C Both electric and magnetic fields
D Nuclear field
Explanation: EM waves carry energy in both electric and magnetic fields, equally divided between them.
A 0.511 MeV
B 5.11 MeV
C 0.000511 MeV
D 51.1 MeV
Explanation: m₀c² = 9.109 × 10⁻³¹ × (3 × 10⁸)² / (1.6 × 10⁻¹³) ≈ 0.511 MeV
A Alpha
B Beta
C Gamma
D All are equal
Explanation: Gamma rays are the most penetrating because they are neutral, high-energy photons with no charge or mass.
A 2 protons and 1 neutron
B 1 proton and 2 neutrons
C 2 protons and 2 neutrons
D 3 protons and 0 neutrons
Explanation: Atomic number 2 means 2 protons; neutrons = mass number - protons = 3 - 2 = 1 neutron.
A 121.6 nm
B 656.3 nm
C 486.1 nm
D 102.6 nm
Explanation: 1/λ = R(1/1² - 1/2²) = R(3/4) → λ = 4/(3R) ≈ 121.6 nm (Lyman alpha line).
A Twice the threshold frequency
B Half the threshold frequency
C The threshold frequency
D Three times the threshold frequency
Explanation: At threshold frequency f₀, KE = hf₀ - φ = 0. The photon energy just equals the work function.
A Speed of particle
B Charge of particle
C Both speed and radius
D Mass of particle
Explanation: T = 2πm/qB is independent of both speed and radius. It depends only on m, q, and B.
A Faraday\'s law
B Lenz\'s law
C Ohm\'s law
D Coulomb\'s law
Explanation: Lenz\'s law gives the direction of induced current, while Faraday\'s law gives the magnitude of induced EMF.
Explanation: Stefan-Boltzmann law: E = σT⁴. Energy radiated is proportional to the fourth power of absolute temperature.
Explanation: λ = h/√(2qVm). λp/λα = √(qα/qp) = √(4e/e) = 2. So ratio is 2:1.