Engineering :: Heat Transfer

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261.

In case of solids, the heat transfer takes place according to

A.	radiation	B.	conduction
C.	convection	D.	Both (A) and (C)

262.

When a body is in thermal equilibrium with its surroundings, the absorptivity and the emissivity of the body are same. This Law is known as

A.	Wein's Law	B.	Kirchhoff's law
C.	Stefan Boltzmann's law	D.	None of the above

263.

The unit of thermal conductivity in M.K.S. unit is

A.	kcal/m/?C	B.	kcal/m/sec?C
C.	kcal/m2/?C sec	D.	None of the above

264.

The overall co-efficient of heat transfer is expressed as

A.	kcal/hr	B.	kcal/m/hr
C.	kcal/m2/hr/?C	D.	None of the above

265.

The equation E = ? AT4 represents

A.	Wein's Law	B.	Kirchhoff's law
C.	Stefan Boltzmann's law	D.	None of the above

266.

The expression (A2-A1)/loge (A2/A1) for a hollow cylinder is known as

A.	Logarithmic mean radius	B.	Mean area of heat transfer
C.	The rate of heat transfer	D.	None of the above

267.

The overall co-efficients of heat transfer is used in the problems of

A.	convection	B.	conduction
C.	radiation	D.	conduction and convection

268.

The equation ?m x T = constant represents

A.	Wein's Law	B.	Kirchhoff's law
C.	Stefan Boltzmann's law	D.	None of the above

269.

In case of liquids and gases, the heat transfer takes place according to

A.	radiation	B.	conduction
C.	convection	D.	Both (A) and (C)

270.

The rate of heat flow between a solid wall and a fluid (in contact with a solid wall) is given by

A.	Wein's Law	B.	Kirchhoff's law
C.	Newton-Rikhman's Law	D.	None of the above