Heat transfer by conduction results due to the transfer of free electrons,
kinetic energy & vibrational energy from one molecule to another.
Conduction heat transfer cannot 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'

1 Answer

Answer :

(B) Between two bodies not in physical contact with each other

Related questions

Description : ____ is the transfer of heat from one particle to another by contact. a. Conduction c. Radiation b. Convection d. Combustion

Last Answer : a. Conduction

Description : In furnaces operating at very high temperature (say) 1250°C, e.g. soaking pit), the maximum heat transfer takes place by (A) Conduction (B) Convection (C) Radiation (D) Cannot be predicted

Last Answer : (C) Radiation

Description : Which of the following wavelengths where absorption of electromagnetic waves becomes peak due to vibrational resonances in the water vapor molecule? A. 1.35 cm and 1.7 mm B. 1.5 mm and 5 mm C. 1.35 dm and 1.7 cm D. 1.5 cm and 5mm

Last Answer : A. 1.35 cm and 1.7 mm

Description : Which of the following wavelengths where absorption of electromagnetic waves becomes peak due to vibrational resonances in the water vapor molecule? A. 1.35 cm and 1.7 mm B. 1.5 mm and 5mm C. 1.35 dm and 1.7cm D. 1.5 cm and 5 mm

Last Answer : A. 1.35 cm and 1.7 mm

Description : Which type of joints is better when the product is subjected to large vibrations: welded or threaded? a) Welded b) Threaded c) Both have same results d) Depends on the magnitude of the vibrational force

Last Answer : a) Welded

Description : Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the (A) Existence of thermal boundary layer (B) Temperature gradient produced ... difference (C) Buoyancy of the bubbles produced at active nucleation site (D) None of these

Last Answer : (D) None of these

Description : For the production of X-rays, the electrons which strike with the target are a) slow moving b) fast moving c) vibrational electrons d) free electrons

Last Answer : b) fast moving

Description : A substance emits energy which is detected as a line emission in the visible region using a spectroscope. The origin of this energy is (a) Vibrational energy of the molecules (b) Rotational energy of the molecules (c) Energy of orbital electrons (d) Energy of protons in the nucleus.

Last Answer : Ans:(c)

Description : Pick out the wrong statement. (A) Fluid movement under the influence of buoyant forces resulting from change in density takes place in case of natural convection (B) The ratio NNu /NRe . Npr is ... convection to that by conduction (D) The Colburn jH factor for heat transfer is given by Nst Npr

Last Answer : (D) The Colburn jH factor for heat transfer is given by Nst Npr

Description : When warm and cold liquids are mixed, the heat transfer is mainly by (A) Conduction (B) Convection (C) Radiation (D) Both (A) & (C

Last Answer : (B) Convection

Description : Heat transfer by __________ is almost absent in case of fluidised bed drying operation. (A) Radiation (B) Conduction (C) Convection (D) Both (B) & (C)

Last Answer : A) Radiation

Description : Heat transfer to the water wall in a high pressure water wall type boiler furnace is mainly by (A) Conduction (B) Convection (C) Radiation (D) Both 'a' & 'b'

Last Answer : Option C

Description : When the ratio of the Grashoff number and to the square of Reynolds number is one, the dominant mechanism of heat transfer is: (A) Free convection (B) Entry length problem in laminar forced ... (developing thermal boundary layer) (C) Mixed convection (both free and forced) (D) Forced convection

Last Answer : (C) Mixed convection (both free and forced)

Description : The number of vibrational modes for CH4 molecule is____. (a) 9 (b) 10 (c) 8 (d) 7

Last Answer : (a) 9

Description : Transfer of heat energy from a heater coil to the cooking vessel takes place through the process of- (1) Convection only (2) Conduction and convection only (3) Radiation and convection only (4) Convection, conduction and radiation

Last Answer : (3) Radiation and convection only Explanation: Conduction is the transfer of heat energy by direct contact, convection is the movement of heat by actual motion of matter; radiation is the transfer of energy with the help of electromagnetic waves.

Description : Fourier's law applies to the heat transfer by (A) Convection (B) Radiation (C) Conduction (D) All (A), (B) & (C)

Last Answer : (C) Conduction

Description : If two bodies of different masses, initially at rest, are acted upon by the same force for the same time, then the both bodies acquire the same - (1) velocity (2) momentum (3) acceleration (4) kinetic energy

Last Answer : (2) momentum Explanation: If two bodies of different masses, initially at rest, are acted upon by the same force for the same time, then the both bodies acquire the same momentum.

Description : If two bodies of different masses, initially at rest, are acted upon by the same force for the same time, then the both bodies acquire the same - (1) velocity (2) momentum (3) acceleration (4) kinetic energy

Last Answer : (2) momentum Explanation: If two bodies of different masses, initially at rest, are acted upon by the same force for the same time, then the both bodies acquire the same momentum.

Description : C and Si both have same lattice structure, having 4 bonding electrons in each. However, C is insulator where as Si is intrinsic semiconductor. This is because (1) The four bonding electrons in the case of C ... the case of C lie in the second orbit, whereas in the case of Si they lie in the third

Last Answer : (4) The four bonding electrons in the case of C lie in the second orbit, whereas in the case of Si they lie in the third

Description : (2) experience collision less frequently Explanation: When an electric field is applied, both the valence electrons and the free electrons move in the same direction. The hole direction is opposite to that ... to free electrons. This means mobility is also less for a hole compared to free electron.

Last Answer : Carbon dioxide is called a greenhouse gas because - (1) its concentration remains always higher than other gases (2) it is used in photosynthesis (3) it absorbs infrared radiation (4) it emits visible radiation

Description : _________ is a measure of the average kinetic energy per molecule in a substance.  a. movement  b. temperature  c. heat  d. mass

Last Answer : temperature

Description : Arithmetic mean area can be used in heat transfer problem to calculate the heat flow by conduction through a cylinder which is (A) Thin walled having the value of Ao Ai /< 2 (B) Thick walled (C) Having the value of Ao /Ai > 2 (D) Both (B) and (C)

Last Answer : (A) Thin walled having the value of Ao Ai /< 2

Description : Heat transfer by radiation between two bodies at T1 & T2 and in an ambient temperature of Ta °C depends on (A) T1 - T2 (B) T1 - Ta (C) T2 - Ta (D) None of these

Last Answer : (D) None of these

Description : During an INELASTIC collision, the colliding bodies w) lose kinetic energy x) keep the same amount of kinetic energy y) gains kinetic energy z) first lose, then gain kinetic energy

Last Answer : ANSWER: W -- LOSE KINETIC ENERGY

Description : If two bodies one light and one heavy have equal kinetic energies, which one has a greater momentum? a.Momentum depends on velocities b.Heavy body c.Both have equal momentum d.Nothing can be concluded on the basis of information provided e.Light body

Last Answer : b. Heavy body

Description : In elastic collisions, A. only the total momentum of the colliding objects is conserved. B. only the total kinetic energy is conserved. C. both of the momentum and total kinetic energy ... D. neither momentum of the colliding bodies nor the total kinetic energy are recoverable.

Last Answer : both of the momentum and total kinetic energy are conserved.

Description : Differences between the M cells and P cells include: a. M cells have larger cell bodies than P cells b. M cells have slower conduction rate than P cells c. M cells have larger receptive field than P cells d. M cells do not synapse in lateral geniculate body whereas P cells do

Last Answer : M cells have larger receptive field than P cells

Description : Heat transfer in the laminar sub-layer in case of a liquid flowing through a pipe, is mostly by (A) Eddies current (B) Conduction (C) Convection (D) None of these

Last Answer : (B) Conduction

Description : The Fourier number (defined as a.t/L 2 ) is used in the analysis of problem involving heat transfer by (A) Forced convection (B) Natural convection (C) Transient conduction (D) Steady state conduction

Last Answer : (C) Transient conduction

Description : In which mode of heat transfer, the Biot number is important? (A) Transient heat conduction (B) Natural convection (C) Forced convection (D) Radiation

Last Answer : (A) Transient heat conduction

Description : Thermal diffusivity is the most important in heat transfer by (A) Conduction (B) Radiation

Last Answer : (A) Conduction

Description : Mode of heat transfer in which the fluid moves under the influence of changes in fluid pressure produced by external work is called (A) Radiation (B) Natural convection (C) Forced convection (D) Conduction

Last Answer : (C) Forced convection

Description : Mode of heat transfer involved in the cooling of air cooled internal combustion engine is (A) Conduction (B) Natural convection (C) Forced convection (D) None of these

Last Answer : (B) Natural convection

Description : If heat transfer rate varies with the time, it is termed as (A) Forced convection (B) Steady state conduction (C) Monochromatic radiation (D) None of these

Last Answer : (D) None of these

Description : Heat transfer by conduction in the turbulent core of a fluid flowing through a heated pipe is negligible, if the value of Prandtl number is (A) 0.2 (B) 0.4 (C) 0.6 (D) 0.8

Last Answer : (C) 0.6

Description : In case of heat transfer by conduction in a hollow cylinder, __________ mean area is used to calculate the heat transfer rate. (A) Geometric (B) Arithmetic (C) Logarithmic (D) Either (A), (B) or (C)

Last Answer : (C) Logarithmic

Description : View factor is important in heat transfer by (A) Steady state conduction (B) Natural convection (C) Forced convection (D) Radiation

Last Answer : (D) Radiation

Description : Heat transfer by __________ may not necessarily require the presence of a medium. (A) Conduction (B) Natural convection (C) Forced convection (D) Radiation

Last Answer : (D) Radiation

Description : Pick out the correct statement. (A) 1 kcal/hr.m.°C is equal to 1 BTU/hr. ft.°F (B) In steady state heat conduction, the only property of the substance which determines the ... in the direction of temperature rise (D) In heat transfer by forced convection, Grashoff number is very important

Last Answer : (B) In steady state heat conduction, the only property of the substance which determines the temperature distribution, is the thermal conductivity

Description : Maximum heat transfer in high temperature furnaces is by (A) Conduction (B) Convection (C) Radiation (D) Either (A), (B) or (C); depends on the type of furnace

Last Answer : (C) Radiation

Description : Gibbs phase rule finds application, when heat transfer occurs by (A) Conduction (B) Convection (C) Radiation (D) Condensation

Last Answer : (D) Condensation

Description : In a furnace with heating element temperature at 1700°C, the dominant mechanism of heat transfer will be (A) Conduction (B) Radiation (C) Natural convection (D) Forced convection

Last Answer : (B) Radiation

Description : reduction in thermal resistance during heat transfer does not occur in the (A) Convection heat transfer by stirring the fluid and cleaning the heating surface (B) Conduction heat transfer by ... Radiation heat transfer by increasing the temperature and reducing the emissivity (D) None of these

Last Answer : Option C

Description : The majority charge carriers in p-type silicon are (A) Free electrons (B) Ions (C) Conduction electrons (D) Holes

Last Answer : Option D

Description : Is the energy in transit (on the move) from the one body or system to another solely because of a temperature between the bodies or systems.  a. Work  b. Heat  c. Energy  d. None of the above

Last Answer : Heat

Description : In case of evaporators, liquid entrainment results primarily due to (A) High vacuum in the evaporator (B) High evaporation rate (C) Foaming of the solution (D) High heat transfer rate

Last Answer : (C) Foaming of the solution

Description : Transfer of genetic information from one bacterium to another in the transduction process is through (a) bacteriophages released from the donor bacterial strain (b) another bacterium ... physical contact between donor and recipient strains (d) conjugation between opposite strain bacterium.

Last Answer : (a) bacteriophages released from the donor bacterial strain

Description : Transfer of genetic information from one bacterium to another in the transduction process is through (a) bacteriophages released from the donor bacterial strain (b) another bacterium ... physical contact between donor and recipient strains (d) conjugation between opposite strain bacterium.

Last Answer : (a) bacteriophages released from the donor bacterial strain

Description : If two different gases have the same volume, temperature, and pressure and behave like ideal gases, they will also be identical in which one of the following ways? w) average molecular velocity x) total mass y) total molecular kinetic energy z) average momentum per molecule

Last Answer : ANSWER: Y -- TOTAL MOLECULAR KINETIC ENERGY

Description : Which of the following statements is TRUE for an ideal gas, but not for a real gas?  A. PV = nRT  B. An increase in temperature causes an increase in the kinetic energy of the gas  C. The ... same as the volume of the gas as a whole  D. No attractive forces exists between the molecule of a gas

Last Answer : PV = nRT