IAT Physics Flashcards

24 sample cards from the Physics deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. State Bernoulli's principle for fluid flow.

   For a streamlined, non-viscous, incompressible flow, P + ½ρv² + ρgh = constant; where the fluid speed is higher, its pressure is lower.

2. State Archimedes' principle.

   A body fully or partly immersed in a fluid experiences an upward buoyant force equal to the weight of the fluid it displaces.

3. Distinguish heat from temperature.

   Heat is energy transferred between bodies due to a temperature difference (a form of energy); temperature is a measure of the average kinetic energy of molecules and determines the direction of heat flow.

4. Name the three modes of heat transfer and the medium each requires.

   Conduction (through solids, no bulk movement of matter), convection (in fluids via bulk movement), and radiation (electromagnetic waves, needs no medium).

5. State the zeroth law of thermodynamics and its significance.

   If two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other; it defines temperature as a measurable property.

6. State the first law of thermodynamics.

   ΔQ = ΔU + ΔW: heat supplied to a system equals the increase in its internal energy plus the work done by the system. It is the law of conservation of energy.

7. For an isothermal and an adiabatic process, what stays constant?

   Isothermal: temperature constant (ΔU = 0, so ΔQ = ΔW). Adiabatic: no heat exchange (ΔQ = 0, so ΔW = -ΔU), and PV^γ = constant.

8. State the second law of thermodynamics (Kelvin-Planck and Clausius statements).

   Kelvin-Planck: no engine can convert heat entirely into work with no other effect. Clausius: heat cannot flow spontaneously from a colder to a hotter body without external work.

9. Give the efficiency of a Carnot engine.

   η = 1 - T_c/T_h, where T_c and T_h are the cold and hot reservoir temperatures in kelvin; it is the maximum possible efficiency between two temperatures.

10. State the key assumptions of the kinetic theory of gases.

    Gas molecules are point masses in constant random motion, with negligible volume and intermolecular forces, undergoing perfectly elastic collisions; time of collision is negligible compared to time between collisions.

11. What is the relation between the average kinetic energy of a gas molecule and temperature?

    Average translational KE per molecule = (3/2)k_BT, where k_B is the Boltzmann constant; it depends only on absolute temperature, not on the gas type.

12. State the law of equipartition of energy.

    In thermal equilibrium, each degree of freedom of a molecule has an average energy of (1/2)k_BT.

13. Define periodic and oscillatory motion, and give the relation between period and frequency.

    Periodic motion repeats at regular intervals; oscillatory motion is periodic motion to-and-fro about a mean position. Frequency f = 1/T (T is the period); SI unit of frequency is hertz (Hz).

14. Define simple harmonic motion (SHM) and its defining force equation.

    SHM is oscillatory motion where the restoring force is directly proportional to displacement and directed toward the mean position: F = -kx, giving acceleration a = -ω²x.

15. Give the time period of a simple pendulum and a spring-mass system.

    Simple pendulum: T = 2π√(L/g). Spring-mass: T = 2π√(m/k), where k is the spring constant.

16. How do kinetic and potential energy vary during SHM?

    Total energy E = ½kA² is constant; KE is maximum at the mean position (zero displacement) and zero at extremes, while PE is maximum at the extremes and zero at the mean position.

17. Differentiate transverse and longitudinal waves with examples.

    In transverse waves particles vibrate perpendicular to wave propagation (e.g., light, string waves); in longitudinal waves particles vibrate parallel to propagation, forming compressions and rarefactions (e.g., sound).

18. State the wave equation relating speed, frequency, and wavelength.

    v = fλ (speed = frequency x wavelength).

19. Give the formula for the speed of a transverse wave on a stretched string.

    v = √(T/μ), where T is the tension and μ is the linear mass density (mass per unit length) of the string.

20. On what factors does the speed of sound in air depend, and how does temperature affect it?

    Speed of sound depends on the medium's properties; in a gas v = √(γP/ρ). It increases with temperature, approximately v ∝ √T (about +0.6 m/s per °C in air).

21. State the principle of superposition of waves.

    When two or more waves overlap, the resultant displacement at any point equals the vector sum of the displacements due to individual waves.

22. What are beats and what is the beat frequency?

    Beats are periodic variations in sound intensity from the superposition of two waves of slightly different frequencies; beat frequency = |f₁ - f₂|.

23. State the Doppler effect for sound.

    The apparent change in frequency of sound due to relative motion between source and observer: frequency increases when they approach and decreases when they recede; f' = f (v ± v_o)/(v ∓ v_s).

24. What is resonance in oscillating systems?

    Resonance occurs when the frequency of an external periodic force equals the natural frequency of a system, producing a large amplitude of oscillation.

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