Physics MDCAT
Mechanics, electricity & modern physics MCQs
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Physics
MDCAT Physics MCQs — mechanics, waves, electricity & modern physics
Answer: E₄/E₂ = (1/4²)/(1/2²) = (1/16)/(1/4) = 4/16 = 1/4. So E₄:E₂ = 1:4
Answer: Nuclear force is the strongest force in nature but operates only over very short range (~10⁻¹⁵ m).
Answer: In radioactive decay, the daughter nucleus has a different atomic number (and often different mass number) than the parent.
Answer: Electron spin was introduced to explain the fine structure of spectral lines and the anomalous Zeeman effect.
Answer: Pauli exclusion principle: no two electrons in an atom can have identical values of all four quantum numbers.
Answer: Δx · Δp ≥ h/4π. Position and momentum cannot both be known with arbitrary precision simultaneously.
Answer: |ψ|² gives the probability density, meaning the probability of finding the particle at a given location.
Answer: P/Q = R/S → 10/20 = 15/S → S = 30 Ω
Answer: Magnetic flux Φ = B·A, SI unit is Weber (Wb) = T·m²
Answer: Parallel currents attract and anti-parallel currents repel each other.
Answer: EM waves carry energy in both electric and magnetic fields, equally divided between them.
Answer: m₀c² = 9.109 × 10⁻³¹ × (3 × 10⁸)² / (1.6 × 10⁻¹³) ≈ 0.511 MeV
Answer: Gamma rays are the most penetrating because they are neutral, high-energy photons with no charge or mass.
Answer: Atomic number 2 means 2 protons; neutrons = mass number - protons = 3 - 2 = 1 neutron.
Answer: 1/λ = R(1/1² - 1/2²) = R(3/4) → λ = 4/(3R) ≈ 121.6 nm (Lyman alpha line).
Answer: At threshold frequency f₀, KE = hf₀ - φ = 0. The photon energy just equals the work function.
Answer: T = 2πm/qB is independent of both speed and radius. It depends only on m, q, and B.
Answer: Lenz\'s law gives the direction of induced current, while Faraday\'s law gives the magnitude of induced EMF.
Answer: Stefan-Boltzmann law: E = σT⁴. Energy radiated is proportional to the fourth power of absolute temperature.
Answer: λ = h/√(2qVm). λp/λα = √(qα/qp) = √(4e/e) = 2. So ratio is 2:1.