Physics MDCAT
Mechanics, electricity & modern physics MCQs
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Physics
MDCAT Physics MCQs — mechanics, waves, electricity & modern physics
Answer: R = 1.097 × 10^7 m⁻¹ is the Rydberg constant used in the hydrogen spectral series formula.
Answer: Transitions to n=2 produce the Balmer series (visible light region).
Answer: ΔE = 13.6(1 - 1/4) = 13.6 × 3/4 = 10.2 eV
Answer: When the plane is parallel to the field, the area vector is perpendicular, giving maximum torque τ = M × B.
Answer: KE_max = q²B²R²/(2m), depending on magnetic field B and radius R of the dees.
Answer: Self-inductance produces a back EMF that opposes any change in current (Lenz\'s law applied to self-induction).
Answer: Energy stored in inductor = ½LI², analogous to energy stored in capacitor = ½CV².
Answer: Z = √(R² + XL²) = √(9 + 16) = √25 = 5 Ω
Answer: tan φ = XC/R = 10/10 = 1 → φ = tan⁻¹(1) = 45°. Current leads voltage.
Answer: At resonance, Z = R (minimum), so power factor cos φ = R/Z = 1. Circuit behaves as purely resistive.
Answer: Number of neutrons = Mass number - Atomic number = 235 - 92 = 143
Answer: Q-value = (mass of reactants - mass of products)c² = total energy released in the nuclear reaction.
Answer: Nuclei must have enough kinetic energy to overcome the Coulomb repulsion between positively charged nuclei.
Answer: In EM waves, E and B fields are perpendicular to each other and both are perpendicular to the direction of wave propagation.
Answer: All electromagnetic waves travel at c = 3 × 10^8 m/s in vacuum.
Answer: Maxwell introduced the concept of displacement current to make Ampere\'s law consistent for time-varying fields.
Answer: Energy density u = ε₀E² = ε₀E₀² sin²(ωt-kx), proportional to the square of the amplitude.
Answer: Poynting vector S = E × B/μ₀ represents the directional energy flux (power per unit area) of the EM wave.
Answer: X-rays are produced when high-speed electrons are suddenly decelerated upon striking a metal target.
Answer: φ = hc/λ₀ = 12400/5000 = 2.48 eV