Mechanical Engineering Mcqs 1919 MCQs [All-Courses]

Mechanical Engineering MCQs prepared for job test and interview preparation, especially for fresh graduates, students, and candidates appearing in competitive exams. These multiple-choice questions cover key topics such as Machine Design, Theory of Machines, Hydraulic Machines, and other important mechanical engineering concepts.

Emissivity of a white polished body in comparison to a black body is________________?

A higher

B lower

C same

D depends upon the shape of body

Review Detailed Answer

Correct Answer: lower

Two balls of same material and finish have their diameters in the ratio of 2 : 1 and both are heated to same temperature and allowed to cool by radiation. Rate of cooling by big ball as compared to smaller one will be in the ratio of____________________?

A 1 :1

B 2: 1

C 1 : 2

D 4 : 1

Review Detailed Answer

Correct Answer: 1 : 2

Heat conducted througfi unit area and unit thick face per unit time when temperature difference between opposite faces is unity,is called__________________?

A thermal resistance

B thermal coefficient

C temperature gradient

D thermal conductivity

Review Detailed Answer

Correct Answer: thermal conductivity

A grey body is one whose absorptivity_________________?

A varies with temperature

B varies with wavelength of the incident ray

C is equal to its emissivity

D does not vary with temperature and. wavelength of the incident ray

Review Detailed Answer

Correct Answer: is equal to its emissivity

The rate of energy emission from unit surface area through unit solid angle, along a normal to the surface, is known as ________________?

A emissivity

B transmissivity

C reflectivity

D intensity of radiation

Review Detailed Answer

Correct Answer: intensity of radiation

In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by___________________?

A convection

B radiation

C conduction

D both convection and conduction

Review Detailed Answer

Correct Answer: conduction

Unit of thermal diffusivity is_________________?

A m2/hr

B m2/hr°C

C kcal/m2 hr

D kcal/m.hr°C

Review Detailed Answer

Correct Answer: m2/hr

Film coefficient is defined as Inside diameter of tube________________?

A Equivalent thickness of film

B Thermal conductivity Equivalent thickness of film Specific heat x Viscocity

C Thermal conductivity Molecular diffusivity of momentum Thermal diffusivity

D Film coefficient x Inside diameter Thermalconductivity

Review Detailed Answer

Correct Answer: Equivalent thickness of film

Thermal conductivity of wood depends on_______________?

A moisture

B density

C temperature

D all of the above

Review Detailed Answer

Correct Answer: all of the above

Thermal diffusivity is ____________________?

A a dimensionless parameter

B function of temperature

C used as mathematical model

D a physical property of the material

Review Detailed Answer

Correct Answer: a physical property of the material

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Mechanical Engineering Mcqs 1919 MCQs [All-Courses]

All Topics 1919

All Topics 1919

Emissivity of a white polished body in comparison to a black body is________________?

Two balls of same material and finish have their diameters in the ratio of 2 : 1 and both are heated to same temperature and allowed to cool by radiation. Rate of cooling by big ball as compared to smaller one will be in the ratio of____________________?

Heat conducted througfi unit area and unit thick face per unit time when temperature difference between opposite faces is unity,is called__________________?

A grey body is one whose absorptivity_________________?

The rate of energy emission from unit surface area through unit solid angle, along a normal to the surface, is known as ________________?

In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by___________________?

Unit of thermal diffusivity is_________________?

Film coefficient is defined as Inside diameter of tube________________?

Thermal conductivity of wood depends on_______________?

Thermal diffusivity is ____________________?