Description : Critical temperature is' the temperature above which (a) a gas will never liquefy (b) a gas will immediately liquefy (c) water will evaporate (d) water will never evaporate
Last Answer : Ans: a
Description : Does the word liquefy have anything to do with the word liquid?
Last Answer : Yes. Liquefy means to turn something into a liquid.
Description : I have a sugar cube made of honey. How to get it back to liquid? thank you for answer
Last Answer : Put the glass in warm (not hot) water.
Description : How do we liquefy gases?
Last Answer : Maybe
Description : Darlene melted a stick of butter and set the liquid butter on the counter. After a few hours, Darlene saw that the butter had become solid again. What happened to cause the liquid butter to turn back into a solid?
Last Answer : The liquid butter has lost heat energy.
Description : Pick out the correct statement. (A) Higher is the temperature of the radiating body, higher is the wavelength of radiation (B) Logarithmic mean area is used for calculating the heat flow rate ... ) Solid angle subtended by the finite surface at the radiating element is called the angle of incidence
Last Answer : (B) Logarithmic mean area is used for calculating the heat flow rate through a thick walled cylinder
Description : 19 Transformer cores are built up from laminations rather than from solid metal so that A. Oil penetrates the core more easily B. Eddy current loss is reduced C. Less lamination is required for the windings D. Turn ratio is higher than voltage ratio
Last Answer : B. Eddy current loss is reduced
Description : What term refers to the heat needed to change a unit mass of a substance at its melting temperature from a solid into a liquid?
Last Answer : ANSWER: HEAT OF FUSION or LATENT HEAT OF FUSION or ENTHALPY OF FUSION
Description : Above image shows an experiment where copper sulphate crystals are heated. When we heat the crystals, they turn white. If you moisten the crystals again with water you will find that colour of crystals reappears . (1 ... are present in one formula unit of copper sulphate (a)5 (b)2 (c)6 (d)7
Last Answer : (a)5
Description : Heat sensitive materials like certain pharmaceuticals and food stuffs can be dried in a/an __________ dryer. (A) Indirect tray (B) Spray (C) Freeze (D) None of these
Last Answer : (C) Freeze
Description : The water from a hand pump is warm in winter because - (1) our body is cold in winter and the water appears to be warm (2) the temperature inside the Earth is higher than the atmospheric ... causes friction which warms up the water (4) inside water comes out and absorbs heat from the environment
Last Answer : (2) the temperature inside the Earth is higher than the atmospheric temperature
Description : The water from a hand pump is warm in winter because - (1) Our body is cold in winter and the water appears to be warm (2) The temperature inside the earth is higher than the atmospheric ... causes friction which warms up the water (4) Inside water comes out and absorbs heat from the environment
Last Answer : (2) The temperature inside the earth is higher than the atmospheric temperature Explanation: In winter, the outside temperature is lower than that of water flowing out of the pump, and therefore, the ... the outside temperature is higher than the water of the pump, and therefore, it feels cold.
Description : Burns caused by steam are much severe than those caused by boiling water because – (1) Steam pierces through the pores of body quickly (2) Steam has latent heat (3) Steam is gas and engulfs the body quickly (4) Temperature of steam is higher
Last Answer : (2) Steam has latent heat Explanation: When water changes into steam, it absorbs latent heat, and when steam condenses to form water, it gives out an equal amount of latent heat. Bums caused ... boiling water, simply because steam contains more heat (in the form of latent heat) than boiling water.
Description : On a cold day when the room temperature is 15°C, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15°C, because - (1) metals ... metals (3) metals are good conductors of heat (4) plastics have a higher thermal conductivity than metals
Last Answer : (3) metals are good conductors of heat Explanation: On a chilly day, the room temperature is lower than our body temperature. Since metals have a higher coefficient of thermal conductivity than plastic, they ... from our fingers will flow to the metal cap much more quickly than to the plastic body.
Description : Heat is transmitted from higher temperature to lower temperature through the actual motion of the molecules in – (1) Conduction (2) Convection (3) Radiation (4) Both conduction and convection
Last Answer : (2) Convection Explanation: The process of heat transfer from one place to an-other place without the movement of particles is called conduction Example: Heat transfer through Metal rods. On the ... heated particles of the substance. The fluids (liquids and gases) are heated by this process.
Description : Heat is transmitted from higher temperature to lower temperature through the actual motion of the molecules in - (1) Conduction (2) Convection (3) Radiation (4) Both conduction and convection
Last Answer : (2) Convection Explanation: The process of heat transfer from one place to another place without the movement of particles is called conduction,
Description : On a cold day when the room temperature is 15°C, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15°C, because : (1) metals ... metals (3) metals are good conductors of heat (4) plastics have a higher thermal conductivity than metals
Last Answer : metals are good conductors of heat
Description : Heat is transmitted from higher temperature to lower temperature through the actual motion of the molecules in (1) Conduction (2) Convection (3) Radiation (4) Both conduction and convection
Last Answer : Convection
Description : Burns caused by steam are much severe than those caused by boiling water because (1) Steam pierces through the pores of body quickly (2) Steam has latent heat (3) Steam is gas and engulfs the body quickly (4) Temperature of steam is higher
Last Answer : Steam has latent heat
Description : The water from a hand pump is warm in winter because (1) Our body is cold in winter and the water appears to be warm (2) The temperature inside the earth is higher than the atmospheric ... causes friction which warms up the water (4) Inside water comes out and absorbs heat from the environment
Last Answer : The temperature inside the earth is higher than the atmospheric temperature
Description : Pick out the wrong statement. (A) In drying a solid containing moisture above the critical moisture content the number of degrees of freedom is 2 (B) Sherwood number in mass transfer corresponds to ... tube heat exchangers. At higher pressure, however, it is customary to put gas in the tube side
Last Answer : (C) Forced convection is relatively more effective in increasing the rate of mass transfer, if Schmidt number is larger
Description : What is the amount of heat needed to turn 1 kg of the substance at its melting point from the solid to liquid state? A. Heat of fusion B. Heat of vaporation C. Heat of condensation D. Heat of fission
Last Answer : Heat of fusion
Description : A solid metallic block weighing 5 kg has an initial temperature of 500°C. 40 kg of water initially at 25°C is contained in a perfectly insulated tank. The metallic block is brought into contact with water. Both of them come to equilibrium. ... .kg-1, K-1is (A) -1.87 (B) 0 (C) 1.26 (D) 3.91
Last Answer : (B) 0
Description : Consider the following four statements (1-4) about certain desert animals such as kangaroo, rat. (1) They have dark colour and high rate of reproduction and excrete solid urine. (2) They do ... water. (4) They excrete very concentrated urine and do not use water to regulate body temperature.
Last Answer : (c) 3 and 4
Description : Pick out the wrong statement. (A) A ferromagnetic material becomes paramagnetic above the 'Curie temperature' (B) Permanent magnets are made of hard materials, whereas electromagnets require soft ... hysterisis loss and coercive forces (D) Tungsten steel and alnico are not hard magnetic materials
Last Answer : Option D
Description : Ceramic nuclear metals compared to solid nuclear metals have (A) Higher melting points (B) Low strength at high temperature (C) More chances of radiation damage (D) Poorer corrosion resistance
Last Answer : (A) Higher melting points
Description : Pick out the wrong statement. (A) The binary diffusivity in liquids is of the order of 10 -5 cm2 /sec (B) Molecular diffusion in solid is much faster than that in liquids ( ... Poiseuille's law, the permeability decreases with increase in temperature for flow of a gas through a given capillary
Last Answer : (B) Molecular diffusion in solid is much faster than that in liquids
Description : Higher efficiency in the combustion of solid fuel cannot be achieved by (A) Proper fuel preparation (B) Keeping the flue gas exhaust temperature very high (C) Adopting efficient-fuel firing technique & equipment (D) Supplying correct quantity of combustion air
Last Answer : (B) Keeping the flue gas exhaust temperature very high
Description : Solid type cables are considered unreliable beyond 66 kV because (a) insulation may melt due to higher temperature (b) skin effect dominates on the conductor (c) of corona loss between conductor and sheath material (d) there is a danger of breakdown of insulation due to the presence of voids
Last Answer : (d) there is a danger of breakdown of insulation due to the presence of voids
Description : A block of wood initially at rest slides down an inclined plane. Neglecting friction, the kinetic energy of the block at the bottom of the plane is: w) all converted into heat x) equal to its ... kinetic energy at the top of the plane z) dependant on the materials of which the block is made
Last Answer : ANSWER: X -- EQUAL TO ITS POTENTIAL ENERGY (WITH RESPECT TO THE BOTTOM OF PLANE) WHEN IT WAS AT THE TOP OF THE PLANE.
Last Answer : : In transportation mode.
Description : The direction of heat flow between two objects depends on - (1) Their masses (2) Their heat contents (3) Their temperatures (4) Whether they are in solid, liquid or gaseous state
Last Answer : (3) Their temperatures Explanation: Heat always flows from a body at higher temperature to a body at a lower temperature.
Description : What propertys of the materials used in computer chips makes them useful as switched that turn electricity on and off?
Last Answer : The silicon is a semiconductor and can be doped to control itsconductivity and create the junctions needed to make diodes andtransistors. These diodes and transistors can act as switches andlogic gates ... beused to attach wires or metal beads so that the chip can beconnected to external circuits.
Description : If you could turn your phone into anything, but at the cost of NEVER using a phone again, what would it be?
Last Answer : In a Portable device that gives me access to the internet, contains a calculator, a compass, a short massage system, a flashlight and other more or less useful apps… but no phone. Or in a portable toaster…
Description : What do you call when the materials in an object are used again?
Last Answer : That's called recycling.
Description : Solids which conduct electricity at higher temperature but not at lower temperature are called (1) super-conductor (2) metallic-conductor (3) semi-conductor (4) insulator
Last Answer : (3) semi-conductor Explanation: Semiconductors are insulators at low temperatures and reasonably good conductors at higher temperatures. As temperature increases, the semiconductor material becomes a better and better conductor.
Last Answer : semi-conductor
Description : Molecular distillation is (A) High temperature distillation (B) For heat-sensitive materials (C) Very low pressure distillation (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : Vacuum is generally maintained in the vapour space of an evaporator mainly to (A) Get economical temperature difference by using moderate pressure steam (B) Facilitate forward ... (C) Concentrate heat sensitive materials (D) Achieve very high concentration of the final product
Last Answer : (A) Get economical temperature difference by using moderate pressure steam
Description : A steam pipe is intended to be insulated with two layers of insulating materials of different thermal conductivities. For minimum heat transfer to take place (A) The better insulation material should be put just ... to which insulating material is to be put inside (i.e., just next to the pipe)
Last Answer : (A) The better insulation material should be put just next to pipe (i.e., inside)
Description : Heating of ferromagnetic materials to a temperature above Curie temperature makes it (A) Insulator for heat & electricity transmission (B) Ferritic (C) Behave like paramagnetic materials (D) Superconductor
Last Answer : Option C
Description : Do you think after a certain age you should have to take a drivers test again?
Last Answer : That is common practice in many places. Mine for example expires when I turn 70 – and that’s a Danish license.
Description : In convection heat transfer, if heat flux intensity is doubled then temperature difference between solid surface and fluid will ?
Last Answer : Get doubled.
Description : Pick out the correct statement. (A) Plastics are good conductors of heat and electricity (B) All the polymers are highly crystalline in nature (C) Polymers can be vaporised by heating to ... D) The liquid polymer becomes greasy, then waxy and finally solid on increasing the degree of polymerisation
Last Answer : (D) The liquid polymer becomes greasy, then waxy and finally solid on increasing the degree of polymerisation
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 : Heat transfer rate to the charge/stock in a furnace does not depend upon the (A) Type of fuels viz. solid, liquid or gaseous (B) Flue gas temperature (C) Emissivity of refractory walls (D) Initial temperature of the charged stock
Last Answer : (A) Type of fuels viz. solid, liquid or gaseous
Description : Pick out the wrong statement. (A) Cp of monatomic gases such as metallic vapor is about 5 kcal/kg.atom (B) The heat capacity of solid inorganic substance is exactly equal to the ... isolated system (D) At absolute zero temperature, the heat capacity for many pure crystalline substances is zero
Last Answer : (C) There is an increase in entropy, when a spontaneous change occurs in an isolated system
Description : With increase in temperature, the atomic heat capacities of all solid elements (A) Increases (B) Decreases (C) Remains unchanged (D) Decreases linearly
Last Answer : (A) Increases
Description : The third law of thermodynamics states that the (A) Heat capacity of a crystalline solid is zero at absolute zero temperature (B) Heat transfer from low temperature to high temperature source is ... without external work (C) Gases having same reduced properties behaves similarly (D) None of these
Last Answer : (A) Heat capacity of a crystalline solid is zero at absolute zero temperature