Q. Cork is a good insulator because

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Q. The heat energy propagation due to conduction heat transfer will be minimum for

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Q. Heat conduction in gases is due to

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Q. Most metals are good conductor of heat because of

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Q. Identify the very good insulator

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Q. The average thermal conductivities of water and air conform to the ratio

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Q. Which one of the following forms of water have the highest value of thermal conductivity?

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Q. Mark the matter with least value of thermal conductivity

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Q. Thermal conductivity is defined as the heat flow per unit time

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Q. Which of the following is the unit of thermal resistance?

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Q. “Thermal conductivity represents the amount of heat conducted across unit area when a temperature difference of one kelvin”. True or false

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Q. Which one is not the unit of thermal conductivity?

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Q. Transmission of heat i.e. molecular is smallest in case of

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Q. Negative sign in Fourier heat conduction equation indicates

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Q. Consider the following statements:

The Fourier heat conduction equation

Q = -k A d t /d x

Presumes

i) Steady state conditions

ii) Constant value of thermal conductivity

iii) Uniform temperature at the wall surface

iv) One dimensional heat flow

Which of these statements are correct?

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Q. Here are some assumptions that are made for Fourier law. Identify the wrong one

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Q. Fourier law of heat conduction is best represented by

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Q. The famous Fourier series is named after

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Q. The diffusion equations
Ɏ²t + q g = (1/α) (d t/d r)
Governs the temperature distribution under unsteady heat flow through a homogenous and isotropic material. The Fourier equation follows from this expression when

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Q. To effect a bond between two metal plates, 2.5 cm and 15 cm thick, heat is uniformly applied through the thinner plate by a radiant heat source. The bonding must be held at 320 K for a short time. When the heat source is adjusted to have a steady value of 43.5 k W/m², a thermocouple installed on the side of the thinner plate next to source indicates a temperature of 345 K. Calculate the temperature gradient for heat conduction through thinner plate. In the diagram, the upper plate is 2.5 cm thick while the lower is 15 cm thick.

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