__________ chart is known as transient heat conduction chart.

Diagram shows transient heat conduction in an infinite plane wall. Identify the correct boundary condition in transient heat conduction in solids with finite conduction

A

t = t i at T = 0

B

d t /d x = 1 at x = 0

C

d t /d x = infinity at x = 1

D

d t / d x = infinity at x = 0

Fourier's law of heat conduction is (where Q = Amount of heat flow through the body in unit time, A = Surface area of heat flow, taken at right angles to the direction of heat flow, dT = Temperature difference on the two faces of the body, dx = Thickness of the body, through which the heat flows, taken along the direction of heat flow and k = Thermal conductivity of the body)

A

$${\text{kA}}\frac{{{\text{dT}}}}{{{\text{dx}}}}$$

B

$${\text{kA}}\frac{{{\text{dx}}}}{{{\text{dT}}}}$$

C

$${\text{k}}\frac{{{\text{dT}}}}{{{\text{dx}}}}$$

D

$${\text{k}}\frac{{{\text{dx}}}}{{{\text{dT}}}}$$

Which of the following is/are the advantages of using a control chart for inspection? (i) A control chart indicates whether the process is in control or out of control. (ii) A control chart determines process variability. (iii) A control chart ensures product quality. (iv) Scrap or percentage reduction can be reduced by taking the necessary actions in time against the warnings indicated by control charts. (v) Control charts build up the reputation of the organization through customer’s satisfaction. (vi) The control chart can detect the unusual variations taking place in a process.

A

i, ii, iii only

B

i, iv, v only

C

i, ii, iii, iv, v and vi

D

iv, v and vi

A Carnot heat engine receives heat at 750 K and rejects the waste heat to the environment at 300 K. The net work output of the heat engine is used to drive a Carnot refrigerator, whose COP is 6.14. If the heat removal rate from the refrigerated space is 6.6 kW, determine the rate of heat supply to the heat engine?

A

2.79 kW

B

1.79 kW

C

4.79 kW

D

7.79 kW

In direct heat conduction welding, heat flow is controlled by a conventional thermal conduction method.

A

True

B

False

There occurs heat conduction and internal heat generation at uniform rate within the conduction medium itself in the following cases (i) Drying of concrete (ii) Chemical processes (iii) Fuel elements in a nuclear reaction Choose the correct option

A

i only

B

ii only

C

i and iii

D

i, ii and iii

Heat transfer by conduction results due to the transfer of free electrons, kinetic energy & vibrational energy from one molecule to another. Conduction heat transfer can not take place

A

Between two bodies in physical contact with each other

B

Between two bodies not in physical contact with each other

C

From one part of a body to the another part of the same body

D

Both B & C

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.

A

– 1000 degree Celsius/m

B

– 2000 degree Celsius/m

C

– 3000 degree Celsius/m

D

– 4000 degree Celsius/m

When Biot number exceeds 0.1 but is less than 100, use is made of Heislers charts for the solution of transient heat conduction.

A

True

B

False

In transient heat conduction, the two significant dimensionless parameters are

A

Reynolds number and Fourier number

B

Reynolds number and Biot number

C

Reynolds number and Prandtl number

D

Biot number and Fourier number

__________ chart is known as transient heat conduction chart.

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