Practice Test GeeksBME - Bachelor of Mechanical Engineering Practice Test
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Heat Transfer Flashcards

6 cards from real BME practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 6 Heat Transfer flashcards as text

  1. Fourier's law of heat conduction states that heat flux is proportional to:

    Answer: Temperature gradient

    Fourier's law states q = -k(dT/dx), meaning heat flux is directly proportional to the negative temperature gradient.

  2. Which mode of heat transfer does not require a medium?

    Answer: Radiation

    Radiation transfers heat via electromagnetic waves and can occur through a vacuum, unlike conduction and convection which require matter.

  3. The Biot number (Bi) in transient heat conduction represents the ratio of:

    Answer: Convective to conductive resistance

    The Biot number Bi = hL/k is the ratio of convective heat transfer resistance at the surface to conductive resistance within the body.

  4. In a fin, the efficiency is defined as the ratio of actual heat transfer to:

    Answer: Maximum possible heat transfer if the entire fin were at base temperature

    Fin efficiency compares actual heat transfer to the ideal case where the whole fin surface is at the base (maximum) temperature.

  5. What is the thermal resistance for conduction through a flat wall?

    Answer: L/(kA)

    For a flat wall, thermal resistance R = L/(kA), analogous to electrical resistance, where L is thickness, k is conductivity, and A is area.

  6. The Nusselt number (Nu) in convective heat transfer is defined as:

    Answer: hL/k

    The Nusselt number Nu = hL/k is the dimensionless convective heat transfer coefficient, representing the ratio of convective to conductive heat transfer.