Description : During the constant rate period of drying of a solid, (A) Increased air humidity decreases the rate of drying (B) Increasing the air temperature decreases the drying rate (C) Surface evaporation of unbound moisture occurs (D) None of these
Last Answer : (C) Surface evaporation of unbound moisture occurs
Description : During summer, we feel comfortable under a fan because it (a) throws cool air on us (b) sets the air in motion, thereby increasing the evaporation of sweat (c) produces convection currents (d) produces air which carries heat away from the body
Last Answer : Ans:(b)
Description : For a given liquid, the rate of evaporation depends on 1. the temperature of the liquid 2. the temperature of air 3. the surface area of the liquid Which of the above factors is/are correct? (a) 1 only (b) 1 and 2 (c) 2 and 3 (d) 1, 2 and 3
Last Answer : Ans:(d)
Description : Rate of evaporation of petrol is greater than that of water at room temperature because: A. petrol molecules do not have any hydrogen bond (Answer) B. petrol is an organic compound C. water molecules have small size D. petrol molecules have greater size
Last Answer : A. petrol molecules do not have any hydrogen bond (Answer)
Description : Water vapour turns into clouds in the atmosphere when: A. It rains B. The temperature rise C. Dew point is reached (Answer) D. Evaporation takes place
Last Answer : C. Dew point is reached (Answer)
Description : Plants are dried up in winter due to frost because – (1) Evaporation does not take place (2) Photosynthesis does not take place at such low temperature (3) Respiration does not take place at low temperature (4) There is mechanical loss of tissues and drought condition prevails
Last Answer : (4) There is mechanical loss of tissues and drought condition prevails Explanation: Respiration does not rely on the sun, so it is possible for plants to respire around the clock. The rate of respiration ... drought in that frozen water is unavailable to the plant. The air is very dry as well.
Description : Plants are dried up in winter due to frost because (1) Evaporation does not take place (2) Photosynthesis does not take place at such low temperature (3) Respiration does not take place at low temperature (4) There is mechanical loss of tissues and drought condition prevails
Last Answer : There is mechanical loss of tissues and drought condition prevails
Description : For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphereis high, then (a) bigger cabinet should be used (b) smaller cabinet should ... tight vapour seal should be used (d) refrigerant with lower evaporation temperature should be used
Last Answer : Ans: c
Description : When pressure is applied on the system, ice ↔ water, then (A) Equilibrium cannot be established (B) More ice will be formed (C) More water will be formed (D) Evaporation of water will take place
Last Answer : (C) More water will be formed
Description : What is crystallisation? Where is it used? Why is this better than simple evaporation technique? -Science
Last Answer : crystallisation is a process that separates a pure solid in the form of its crystals from a solution. Crystallisation is better than evaporation because during Evaporation. Some solids decompose or some, ... charred on heating to dryness. ... In such cases, the crystallisation technique is applied.
Description : What are the factors affecting evaporation? Explain how rate of evaporation affects by them. -Maths 9th
Last Answer : Factors That Affect the Rate of Evaporationtemperature of the liquid. A cup of hot water will evaporate more quickly than a cup of cold water.exposed surface area of the liquid. ...presence or ... substances in the liquid. ...air movement. ...concentration of the evaporating substance in the air.
Description : What is the rate of evaporation when the pressure decreases ?
Last Answer : As the pressure decreases, the rate of evaporation increases.
Description : Why does a liquids evaporation rate increases when liquid is heated?
Last Answer : More molecules have enough energy to overcome the attractiveforces holding them in the liquid.
Description : Transpiration differs from evaporation in: (a) Rate of water loss (b) Transpiration is a physiological process while evaporation is physical process (c) Transpiration is physical process while evaporation is physiological process (d) Frequency of water loss
Last Answer : Ans. ((b))
Description : When the rate of evaporation of water is zero, the relative humidity of the air is A. 0% B. 100% C. 50% D. unpredictable
Last Answer : ANSWER : B
Description : Extensive deserts occur in the western tropical regions of continents because : (1) of easterly trade winds. (2) cold ocean currents flow along the western coasts. (3) of the effect of both the ... winds and cold ocean currents. (4) the rate of evaporation is greater along the western margin areas.
Last Answer : (3) of the effect of both the off-shore easterly trade winds and cold ocean currents. Explanation: Extensive deserts occur in the western tropical regions of continents because of the effect of ... is found near the tropics of Cancer and Capricorn, usually toward the western side of the continents
Description : In the constant rate period of the rate of drying curve for batch drying, (A) Cracks develop on the surface of the solid (B) Rate of drying decreases abruptly (C) Surface evaporation of unbound moisture occurs (D) None of these
Description : The number of kg vaporised per kg of steam fed to the evaporator is defined as (A) Capacity (B) Rate of evaporation (C) Economy (D) Rate of vaporisation
Last Answer : (C) Economy
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 : The rate of evaporation from reservoirs may be determined by (A) Pan-measurement method (B) Empirical formulae (C) Storage equation method (D) All the above
Last Answer : Answer: Option D
Description : For calculating the evaporation rate over a reservoir surface E = 0.771 (1.465 - 0.00732B) (0.44 - 0.007375 V) (pe - pa), the equation is given by (A) Roohwer's, formula in M.K.S. (B) Roohwer's formula in F.P.S. (C) Dalton's formula in F.P.S. (D) Dalton's formula in M.K.S
Last Answer : Answer: Option A
Description : What Are The Factors That Affect The Rate Of Evaporation Of Water In Cooling Towers?
Last Answer : Amount of water surface area exposed. The time of exposure. The relative velocity of air passing over the droplets. The RH of air. The direction of airflow relative to water.
Description : Explain the factors which affect the rate of evaporation of a liquid.
Last Answer : Factors affecting rate of evaporation: 1. Temperature: The rate of evaporation is directly proportional to the temperature of liquid. The evaporation can be accelerated by increasing the temp ... : The rate of evaporation is directly proportional to the vapour pressure of evaporating liquid.
Description : Describe the factors which affect rate of the evaporation of liquid
Last Answer : Factors affecting evaporation: 1)Temperature: The rate of evaporation is directly proportional to temp of liquid. 2)Temperature and time of evaporation: It has been observed that exposure to ... : The rate of evaporation is directly proportional to the vapour pressure of the evaporating liquid.
Description : Define evaporation. Explain any four factors affecting rate of evaporation.
Last Answer : Definition: Evaporation is the free escape of vapour from the surface of a liquid bellow its boiling point. Factors affecting rate of evaporation: 1. Temperature: The rate of evaporation is ... The rate of evaporation is maximum at its boiling point when the liquid has maximum vapour pressure.
Last Answer : of the effect of both the offshore easterly trade winds and cold ocean currents.
Description : Water is a highly effective coolant for a car engine because -----? A. Water is good conductor of heat B. Water has very high specific heat capacity (Answer) C. Water boils at a comparatively high temperature D. Evaporation of water produces lot of cooling
Last Answer : B. Water has very high specific heat capacity (Answer)
Description : Rate of leaching increases with increasing (A) Temperature (B) Viscosity of solvent (C) Pressure (D) Size of the solid
Last Answer : (A) Temperature
Description : With reference to factors affecting the rate of photosynthesis, which of the following statements is not correct? (a) Increasing atmospheric CO2 concentration up to 0.05% can enhance CO2 fixation rate. ( ... for higher yield. (d) Light saturation for CO2 fixation occurs at 10% of full sunlight.
Last Answer : (b) C3 plants respond to higher temperature with enhanced photosynthesis while C4 plants have much lower temperature optimum
Description : Conversion achieved in HNO3 synthesis with the use of platinum catalyst is about 95-97%. The rate of formation of nitrogen dioxide from the oxidation of nitric acid is favoured by (A) Decreasing the pressure (B) Decreasing the temperature (C) Increasing the temperature (D) None of these
Last Answer : (C) Increasing the temperature
Description : The rate constant of a chemical reaction increases by increasing the (A) Temperature (B) Pressure (C) Reactant's concentration (D) None of these
Description : Pick out the wrong statement pertaining to solvent extraction of oil. Rate of extraction (A) Decreases with decrease of thickness of the flakes (B) Increases with the increasing flake size ... considerably with the rise of temperature (D) Decreases as the moisture content of flakes increases
Last Answer : (D) Decreases as the moisture content of flakes increases
Description : With reference to factors affecting the rate of photosynthesis, which of the following statements is not correct ? (1) Increasing atmospheric CO 2 concentration up to 0.05% can enhance CO 2 fixation ... for higher yield (4) Light saturation for CO 2 fixation occurs at 10% of full sunlight
Last Answer : (2) C 3 plants respond to higher temperatures with enhanced photosynthesis while C 4 plants have much lower temperature optimum
Description : The presence of ozone in the stratosphere is responsible for (1) increasing the average global temperature in recent years (2) higher rate of photosynthesis (3) checking the penetration of ultra-violet rays to the earth (4) supplying oxygen for people travelling in jets
Last Answer : checking the penetration of ultra-violet rays to the earth
Description : Reducing suction pressure in refrigeration cycle (a) lowers evaporation temperature (b) increases power required per ton of refrigeration (c) lowers compressor capacity because vapour is lighter (d) all of the above.
Last Answer : Ans: d
Description : Water is a highly effective coolant for a car engine because _____ A. Water is good conductor of heat B. Water has very high specific heat capacity C. Water boils at a comparatively high temperature D. Evaporation of water produces lot of cooling
Last Answer : ANSWER: A
Description : For the air water system under ambient conditions, the adiabatic saturation temperature and the wet bulb temperature are nearly equal, because (A) Water has a high latent heat of evaporation (B) Lewis number is close to unity (C) They are always equal under all circumstances
Last Answer : (A) Water has a high latent heat of evaporation
Description : Applying Le- Chatelier's principle, predict the effect of temperature and pressure on evaporation of water.
Last Answer : Ans Evaporation of water can be represented as water + heat water vapours: i) With increase in pressure- the equilibrium tend to shift in direction where there is decrease in the vol. i.e. ... left. ii) with increase in temperature- the equilibrium shifts to right as it is an endothermic reaction.
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 : The outlet temperature of cooling water in a heat exchanger is generally not allowed to exceed above 50°C in industrial practice mainly to avoid (A) Its evaporation loss (B) Excessive corrosion (C) Uneconomic LMTD (D) Decrease in heat exchanger efficiency
Last Answer : (B) Excessive corrosion
Description : Which one of the following statements is correct with respect to kidney function regulation? (a) When someone drinks lot of water, ADH release is suppressed. (b) Exposure to cold temperature ... During summer when body loses lot of water by evaporation, the release of ADH is suppressed.
Last Answer : (a) When someone drinks lot of water, ADH release is suppressed.
Description : The burnout heat flux in the nucleate boiling regime is not a function of the (A) Liquid density (B) Vapour density (C) Temperature difference (D) Heat of evaporation
Last Answer : (B) Vapour density
Description : The use of pressurized radiator cap is to a) Reduce evaporation loss b) Increase engine operating temperature c) Increase boiling point of water d) Reduce heat losses
Last Answer : ans c
Description : Consider the diurnal (daily) cycle of temperature at the surface. Why is the tem- perature maximum in the mid-to-late afternoon? (a) There is a net energy gain at the surface from dawn to mid- ... this time. (d) Late in the day, evaporation from the surface increases and this cools the surface.
Last Answer : There is a net energy gain at the surface from dawn to mid- afternoon.
Description : Evaporation from water surfaces exposed to air is not dependent of the: w) velocity of the wind x) humidity y) temperature z) depth of the water
Last Answer : ANSWER: Z -- DEPTH OF THE WATER
Description : With increasing flow rate, the hydraulic efficiency of a centrifugal pump (A) Monotonically decreases (B) Decreases and then increases (C) Remains constant (D) Increases and then decreases
Last Answer : (A) Monotonically decreases
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 : Pick out the wrong statement (A) A horizontal line on the humidity chart indicates the temperature changes at constant molal humidity (B) When water is cooled from 80 to 70°C by exposure ... & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure
Last Answer : (D) Relative saturation of unsaturated mixture of water vapor & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure
Description : Q8. For increasing production, what is common in poultry, fisheries and bee-keeping? -Science
Last Answer : For increasing production, cross breeding techniques are used adopted in poultry, fisheries and bee-keeping. Along with these technique regular and proper maintenance methods are useful in improving the production.