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GATE ME 2017 Set 2

MCQ (Single Correct Answer)

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-0.67

A metal ball of diameter $$60mm$$ is initially at $${220^ \circ }C.$$ The ball is suddenly cooled by an air jet of $${20^ \circ }C.$$ The heat transfer coefficient is $$200\,W/{m^2}.K.$$ The specific heat, thermal conductivity and density of the metal ball are $$400\,\,J/kg.K,\,\,400\,\,W/m.K$$ and $$\,9000\,\,kg/{m^3},$$ respectively. The ball temperature (in $${}^ \circ C$$) after $$90$$ seconds will be approximately.

2

GATE ME 2016 Set 1

Numerical

+2

-0

A steel ball of $$10$$ $$mm$$ diameter at $$1000$$ $$K$$ is required to be cooled to $$350$$ $$K$$ by immersing it in a
water environment at $$300$$ $$K.$$ The convective heat transfer coefficient is $$1000\,\,W/{m^2}$$-$$K.$$ Thermal
conductivity of steel is $$40$$ $$W/m$$-$$K.$$ The time constant for the cooling process $$\tau $$ is $$16s.$$ The time
required (in $$s$$) to reach the final temperature is __________________.

Your input ____

3

GATE ME 2016 Set 2

Numerical

+2

-0

Two cylindrical shafts $$A$$ and $$B$$ at the same initial temperature are simultaneously placed in a furnace. The surfaces of the shafts remain at the furnace gas temperature at all times after they are introduced into the furnace. The temperature variation in the axial direction of the shafts can be assumed to be negligible. The data related to shafts $$A$$ and $$B$$ is given in the following Table.

The temperature at the center-line of the shaft $$A$$ reaches $${400^ \circ }C$$ after two hours. The time required (in hours) for the center-line of the shaft $$B$$ to attain the temperature of $${400^ \circ }C$$ is ____________

Your input ____

4

GATE ME 2016 Set 3

Numerical

+2

-0

A cylindrical steel rod, $$0.01$$ $$m$$ in diameter and $$0.2$$ $$m$$ in length is first heated to $${750^ \circ }C$$ and then immersed in a water bath at $${100^ \circ }C.$$ The heat transfer coefficient is $$250\,W/{m^2}$$-$$K.$$ The density, specific heat and thermal conductivity of steel are $$\rho = 7801\,\,kg/{m^3},$$ $$c = 473$$ $$J/kg$$-$$K,$$ and $$k = 43$$ $$W/m$$-$$K,$$ respectively. The time required for the rod to reach $${300^ \circ }C$$ is ________ seconds.

Your input ____

Questions Asked from Fin Design and Transient Heat Conduction (Marks 2)

Number in Brackets after Paper Indicates No. of Questions

GATE ME Subjects

Engineering Mechanics

Strength of Materials

Theory of Machines

Engineering Mathematics

Machine Design

Fluid Mechanics

Turbo Machinery

Heat Transfer

Thermodynamics

Production Engineering

Industrial Engineering

General Aptitude