Heat Transfer MCQs

Option A: absolute temperature (T)

Option B: I2

Option C: f

Option D: t

Correct Answer: absolute temperature (T) ✔

Option A: p = 0, x = 0 and a = 1

Option B: p=l,x = 0anda = 0

Option C: p = 0, x = 1 and a = 0

Option D: x – 0, a + p = 1

Correct Answer: x – 0, a + p = 1 ✔

Option A: p = 0, x = 0 and a = 1

Option B: p=l,T = 0anda = 0

Option C: p = 0, x = 1 and a = 0

Option D: x = 0, a + p = 1

Correct Answer: p=l,T = 0anda = 0 ✔

Option A: Krichoff’s law

Option B: Stefan’s law

Option C: Wien’ law

Option D: Planck’s law

Correct Answer: Krichoff’s law ✔

Option A: less than those for gases

Option B: jess than those for liquids

Option C: more than those for liquids and gases

Option D: more or less same as for liquids and gases

Correct Answer: more than those for liquids and gases ✔

Option A: absolute temperature

Option B: T2

Option C: T5

Option D: t

Correct Answer: t ✔

Option A: p = 0, x = 0 and a = 1

Option B: p= l,T = 0anda = 0

Option C: p = 0, x = 1 and a = 0

Option D: x = 0, a + p = 0

Correct Answer: p = 0, x = 0 and a = 1 ✔

Option A: temperature

Option B: thickness

Option C: area

Option D: time

Correct Answer: time ✔

Option A: 0.45

Option B: 0.55

Option C: 0.40

Option D: 0.75

Correct Answer: 0.45 ✔

Option A: temperature

Option B: wave length

Option C: physical nature

Option D: all of the above

Correct Answer: all of the above ✔

Option A: absorptive power

Option B: emissive power

Option C: absorptivity

Option D: emissivity

Correct Answer: absorptive power ✔

Option A: nature of body

Option B: temperature of body

Option C: type of surface of body

Option D: all of the above

Correct Answer: all of the above ✔

Option A: at all temperatures

Option B: at one particular temperature

Option C: when system is under thermal equi-librium

Option D: at critical temperature

Correct Answer: when system is under thermal equi-librium ✔

Option A: p = 0, x = 0 and a = 1

Option B: p=l,x = 0,anda = 0

Option C: p = 0, T= l,anda = 0

Option D: X = 0, a + p = 1

Correct Answer: p = 0, T= l,anda = 0 ✔

Option A: convection

Option B: free convection

Option C: forced convection

Option D: radiation

Correct Answer: radiation ✔

Option A: direct mixing of hot and cold fluids

Option B: a complete separation between hot and cold fluids

Option C: flow of hot and cold fluids alternately over a surface

Option D: generation of heat again and again

Correct Answer: flow of hot and cold fluids alternately over a surface ✔

Option A: 3

Option B: 6

Option C: 9

Option D: 27

Correct Answer: 81 ✔

Option A: is black in colour

Option B: reflects all heat

Option C: transmits all heat radiations

Option D: abslprbs heat radiations of all wave lengths falling on it

Correct Answer: abslprbs heat radiations of all wave lengths falling on it ✔

Option A: black bodies

Option B: polished bodies

Option C: all coloured bodies

Option D: all of the above

Correct Answer: black bodies ✔

Option A: varies with temperature

Option B: varies with the wave length of incident ray

Option C: varies with both

Option D: does not vary with temperature and wave length of the incident ray

Correct Answer: does not vary with temperature and wave length of the incident ray ✔

Option A: more than those for liquids

Option B: less than those for liquids

Option C: more than those for solids

Option D: dependent on the viscosity

Correct Answer: more than those for liquids ✔

Option A: directly proportional to thermal con¬ductivity

Option B: inversely proportional to density of substance

Option C: inversely proportional to specific heat

Option D: all of the above

Correct Answer: all of the above ✔

Option A: conduction

Option B: convection

Option C: radiation

Option D: conduction and radiation combined

Correct Answer: radiation ✔

Option A: watt/cm2 °K

Option B: watt/cm4 °K

Option C: watt2/cm °K4

Option D: watt/cm2 °K4

Correct Answer: watt/cm2 °K ✔

Option A: same

Option B: more

Option C: less

Option D: depends on other factors

Correct Answer: more ✔

Option A: absolute temperature

Option B: square of temperature

Option C: fourth power of absolute temperature

Option D: fourth power of temperature

Correct Answer: absolute temperature ✔

Option A: Grashoff no. and Reynold no

Option B: Grashoff no and Prandtl no.

Option C: Prandtl no. and Reynold no

Option D: Grashoff no., Prandtl no and Reynold no

Correct Answer: Grashoff no and Prandtl no. ✔

Option A: thermal conductivity

Option B: thermal diffusivity

Option C: density

Option D: dynamic viscosity

Correct Answer: density ✔

Option A: shorter wavelength

Option B: longer wavelength

Option C: remains same at all wavelengths

Option D: wavelength has nothing to do with it

Correct Answer: shorter wavelength ✔

Option A: 0.1

Option B: 0.3

Option C: 0.7

Option D: 1.7

Correct Answer: 0.7 ✔

Option A: same

Option B: higher

Option C: more or less same

Option D: very much lower

Correct Answer: very much lower ✔

Option A: Wien’s law

Option B: Planck’s law

Option C: Stefan’s law

Option D: Fourier’s law

Correct Answer: Wien’s law ✔

Option A: kcal/m2

Option B: kcal/hr °C

Option C: kcal/m2 hr °C

Option D: kacl/m hr °C

Correct Answer: kcal/m2 ✔

Option A: reflected

Option B: refracted

Option C: transmitted

Option D: absorbed

Correct Answer: absorbed ✔

Option A: grey body

Option B: brilliant white polished body

Option C: red hot body

Option D: black body

Correct Answer: black body ✔

Option A: universal gas constant

Option B: kinematic viscosity

Option C: thermal conductivity

Option D: Planck’s constant

Correct Answer: Planck’s constant ✔

Option A: conduction

Option B: convection

Option C: radiation

Option D: conduction and convection

Correct Answer: conduction ✔

Option A: both the fluids at inlet (of heat ex¬changer where hot fluid enters) are in their coldest state

Option B: both the fluids at inlet are in their hot¬test state

Option C: both the fluids .at exit are in their hottest state

Option D: one fluid is in hottest state and other in coldest state at inlet

Correct Answer: both the fluids at inlet are in their hot¬test state ✔

Option A: one dimensional cases only

Option B: two dimensional cases only

Option C: three dimensional cases only

Option D: regular surfaces having non-uniform temperature gradients

Correct Answer: one dimensional cases only ✔

Option A: higher

Option B: lower

Option C: same

Option D: depends on the area of heat exchanger

Correct Answer: higher ✔

Option A: radiant heat is proportional to fourth power of absolute temperature

Option B: emissive power depends on temperature

Option C: emissive power and absorptivity are constant for all bodies

Option D: ratio of emissive power to absorptive power is maximum for perfectly black body

Correct Answer: ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body ✔

Option A: better insulation should be put over pipe and better one over it

Option B: inferior insulation should be put over pipe and better one over it

Option C: both may be put in any order

Option D: whether to put inferior OIL over pipe or the better one would depend on steam temperature

Correct Answer: better insulation should be put over pipe and better one over it ✔

Option A: cold water inlet and outlet

Option B: hot medium inlet and outlet

Option C: hot medium outlet and cold water inlet

Option D: hot medium outlet and cold water outlet

Correct Answer: hot medium outlet and cold water outlet ✔

Option A: Grashoff number

Option B: Nusselt number

Option C: Weber number

Option D: Prandtl number

Correct Answer: Grashoff number ✔

Option A: higher

Option B: lower

Option C: same

Option D: depends upon the shape of body

Correct Answer: lower ✔

Option A: 1 :1

Option B: 2: 1

Option C: 1 : 2

Option D: 4 : 1

Correct Answer: 1 : 2 ✔

Option A: thermal resistance

Option B: thermal coefficient

Option C: temperature gradient

Option D: thermal conductivity

Correct Answer: thermal conductivity ✔

Option A: varies with temperature

Option B: varies with wavelength of the incident ray

Option C: is equal to its emissivity

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

Correct Answer: is equal to its emissivity ✔

Option A: emissivity

Option B: transmissivity

Option C: reflectivity

Option D: intensity of radiation

Correct Answer: intensity of radiation ✔

Option A: convection

Option B: radiation

Option C: conduction

Option D: both convection and conduction

Correct Answer: conduction ✔

Option A: m2/hr

Option B: m2/hr°C

Option C: kcal/m2 hr

Option D: kcal/m.hr°C

Correct Answer: m2/hr ✔

Option A: Equivalent thickness of film

Option B: Thermal conductivity Equivalent thickness of film Specific heat x Viscocity

Option C: Thermal conductivity Molecular diffusivity of momentum Thermal diffusivity

Option D: Film coefficient x Inside diameter Thermalconductivity

Correct Answer: Equivalent thickness of film ✔

Option A: moisture

Option B: density

Option C: temperature

Option D: all of the above

Correct Answer: all of the above ✔

Option A: a dimensionless parameter

Option B: function of temperature

Option C: used as mathematical model

Option D: a physical property of the material

Correct Answer: a physical property of the material ✔

Option A: high thickness of insulation

Option B: high vapour pressure

Option C: less thermal conductivity insulator

Option D: a vapour seal

Correct Answer: a vapour seal ✔

Option A: its temperature

Option B: nature of the body

Option C: kind and extent of its surface

Option D: all of the above

Correct Answer: all of the above ✔

Option A: aluminium

Option B: steel

Option C: brass

Option D: copper

Correct Answer: aluminium ✔

Option A: directly proportional to the surface area of the body

Option B: directly proportional to the temperature difference on the two faces of the body

Option C: dependent upon the material of the body

Option D: inversely proportional to the thickness of the body

Correct Answer: all of the above ✔

Option A: different heat contents

Option B: different specific heat

Option C: different atomic structure

Option D: different temperatures

Correct Answer: different temperatures ✔

Option A: glass

Option B: water

Option C: plastic

Option D: rubber

Correct Answer: air ✔

Option A: composition

Option B: density

Option C: porosity

Option D: structure

Correct Answer: all of the above ✔

Option A: it is impossible to transfer heat from low temperature source to t high temperature source

Option B: heat transfer by radiation requires no medium

Option C: all bodies above absolute zero emit radiation

Option D: heat transfer in most of the cases takes place by combination of conduction, convection and radiation

Correct Answer: all bodies above absolute zero emit radiation ✔

Option A: proportional of thermal conductivity

Option B: inversely proportional to k

Option C: proportional to (k)

Option D: inversely proportional to k2

Correct Answer: proportional of thermal conductivity ✔

Option A: I

Option B: 0.5

Option C: 2

Option D: 0.25

Correct Answer: 2 ✔

Option A: electric heater

Option B: steam condenser

Option C: melting of ice

Option D: refrigerator condenser coils

Correct Answer: boiler ✔

Option A: quantity of heat flowing in one second through one cm cube of material when opposite faces ^re maintained at a temperature difference of 1°C

Option B: quantity of heat flowing in one second through a slab of the material of area one cm square, thickness 1 cm when its faces differ in temperature by 1°C

Option C: heat conducted in unit time across unit area through unit thickness when a temperature difference of unity is maintained between opposite faces

Option D: all of the above

Correct Answer: all of the above ✔

Option A: steam

Option B: solid ice

Option C: melting ice

Option D: water

Correct Answer: solid ice ✔

Option A: hr (time)

Option B: sqm (area)

Option C: °C (temperature)

Option D: cm (thickness)

Correct Answer: cm (thickness) ✔

Option A: the time taken to attain the final temperature to be measured

Option B: the time taken to attain 50% of the value of initial temperature difference

Option C: the time taken to attain 63.2% of the value of initial temperature difference

Option D: determined by the time taken to reach 100°C from 0°C

Correct Answer: the time taken to attain 63.2% of the value of initial temperature difference ✔

Option A: 0.1

Option B: 0.23

Option C: 0.42

Option D: 0.51

Correct Answer: 0.51 ✔

Option A: change vapour into liquid

Option B: change liquid into vapour

Option C: increase the temperature of a liquid or vapour

Option D: convert water into steam and superheat it

Correct Answer: convert water into steam and superheat it ✔

Option A: increases

Option B: decreases

Option C: remains constant

Option D: may increase or decrease depending on temperature

Correct Answer: increases ✔

Option A: 0.002

Option B: 0.02

Option C: 0.01

Option D: 0.1

Correct Answer: 0.02 ✔

Option A: free electrons

Option B: atoms colliding frequency

Option C: low density

Option D: porous body

Correct Answer: porous body ✔

Option A: their atoms collide frequently

Option B: their atoms-are relatively far apart

Option C: they contain free electrons

Option D: they have high density

Correct Answer: their atoms collide frequently ✔

Option A: thermometer

Option B: radiatiouv pyrometer

Option C: thermistor

Option D: thermocouple

Correct Answer: thermocouple ✔

Option A: increases

Option B: decreases

Option C: remains constant

Option D: may increase or decrease depending on temperature

Correct Answer: may increase or decrease depending on temperature ✔

Option A: I.C. engine

Option B: air preheaters

Option C: heating of building in winter

Option D: all of the above

Correct Answer: none of the above ✔

Option A: blast furnace

Option B: heating of building

Option C: cooling of parts in furnace

Option D: heat received by a person from fireplace

Correct Answer: heat received by a person from fireplace ✔

Option A: face area

Option B: time

Option C: thickness

Option D: temperature difference

Correct Answer: thickness ✔

Option A: conduction

Option B: convection

Option C: radiation

Option D: conduction and convection

Correct Answer: convection ✔

Option A: J/m2 sec

Option B: J/m °K sec

Option C: W/m °K

Option D: A. and C. above

Correct Answer: E. B. and C. above ✔

Option A: conduction

Option B: convection

Option C: radiation

Option D: scattering

Correct Answer: conduction ✔

Option A: change vapour into liquid

Option B: change liquid into vapour

Option C: increase the temperature of a liquid of vapour

Option D: convert water into steam and superheat it

Correct Answer: increase the temperature of a liquid of vapour ✔

Option A: increases

Option B: decreases

Option C: remains constant

Option D: may increase or decrease depending on temperature

Correct Answer: decreases ✔

Option A: conduction

Option B: convection

Option C: radiation

Option D: conduction and convection

Correct Answer: conduction ✔

Option A: kcal/kg m2 °C

Option B: kcal-m/hr m2 °C

Option C: kcal/hr m2 °C

Option D: kcal-m/hr °C

Correct Answer: kcal-m/hr m2 °C ✔

Option A: increases

Option B: decreases

Option C: remains constant

Option D: may increase or decrease depending on temperature

Correct Answer: decreases ✔

Option A: increase

Option B: decrease

Option C: remain unaffected

Option D: may increase/decrease depending on temperature and thickness of insulation

Correct Answer: decrease ✔

Option A: liquids

Option B: energy

Option C: temperature

Option D: entropy

Correct Answer: temperature ✔

Option A: conduction

Option B: convection

Option C: radiation

Option D: conduction and convection

Correct Answer: radiation ✔

Option A: zeroth law of thermodynamics

Option B: first law of thermodynamic

Option C: second law of the thermodynamics

Option D: Kirchoff’s law E. Stefan’s law

Correct Answer: second law of the thermodynamics ✔