What is meant by humidity and dew point ?

What is meant by humidity and dew point ?
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Humidity in daily life means relative humidity. Relative humidity is the partial pressure of water vapor in the air of a particular place and the saturated vapor pressure of water vapor at that temperature. The amount of water vapor in the air of a place is indicated by the amount of dry or wet humidity in the air. * Dew point: The ability of air to hold water vapor of a certain volume at a certain temperature is limited. As the temperature rises, the water vapor holding capacity of the place increases When the temperature of a place decreases, the water vapor holding capacity of that place decreases As the temperature gradually decreases, the atmosphere at a certain temperature is saturated by the water vapor of the place. At that temperature, the water vapor in the air then turns into dew This temperature is dew point
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Related questions

What is the dew-point when the dry bulb temperature is 20C and the relative humidity is 17?

Description : What is the dew-point when the dry bulb temperature is 20C and the relative humidity is 17?

Last Answer : at 17% relative humidity the dew point is -5.8C at a dry bulb of20C

When dew point la reached it is said that at that temperature (a) the atmosphere is said to be saturated with water vapour (b) the relative humidity of the atmosphere is 100% (c) the atmosphere can hold no more water vapour (d) All the above

Description : When dew point la reached it is said that at that temperature (a) the atmosphere is said to be saturated with water vapour (b) the relative humidity of the atmosphere is 100% (c) the atmosphere can hold no more water vapour (d) All the above

Last Answer : Ans: (a)

Wet-bulb temperature is: a. The temperature indicated by a thermometer whose bulb covered by a water-wetted wick and exposed to a rapidly moving stream of air b. The same as the dry-bulb temperature if the relative humidity is less than 100% c. The dew point temperature d. Always less than the dry-bulb temperature e. Not required to find the relative humidity

Description : Wet-bulb temperature is: a. The temperature indicated by a thermometer whose bulb covered by a water-wetted wick and exposed to a rapidly moving stream of air b. The same as the dry-bulb ... point temperature d. Always less than the dry-bulb temperature e. Not required to find the relative humidity

Last Answer : Answer: A

A device for measuring relative humidity is called: a. A dew point analyzer b. An R. H. gauge c. An aspirating gauge d. A psychrometer e. A chronometer

Description : A device for measuring relative humidity is called: a. A dew point analyzer b. An R. H. gauge c. An aspirating gauge d. A psychrometer e. A chronometer

Last Answer : Answer: D

Dry-bulb temperature is: a. The absolute temperature corresponding to the atmospheric pressure b. The same as the wet-bulb temperature if the relative humidity is less than 100% c. Not required to find the relative humidity d. The temperature of the air measured with an ordinary thermometer e. The dew point temperature

Description : Dry-bulb temperature is: a. The absolute temperature corresponding to the atmospheric pressure b. The same as the wet-bulb temperature if the relative humidity is less than 100% c. Not required ... d. The temperature of the air measured with an ordinary thermometer e. The dew point temperature

Last Answer : Answer: D

At 100% relative humidity, the wet bulb temperature is A. lower than the dew point temperature B. higher than the dew point temperature C. equal to the dew point temperature D. none of the above

Description : At 100% relative humidity, the wet bulb temperature is A. lower than the dew point temperature B. higher than the dew point temperature C. equal to the dew point temperature D. none of the above

Last Answer : ANSWER : C

When the dew point temperature is equal to the air temperature then the relative humidity is A. 0% B. 50% C. 100% D. unpredictable

Description : When the dew point temperature is equal to the air temperature then the relative humidity is A. 0% B. 50% C. 100% D. unpredictable

Last Answer : ANSWER : C

With increase in absolute humidity, the dew point of an unsaturated mixture of air and water vapor (at constant pressure and temperature). (A) Increases (B) Remains unchanged (C) Decreases (D) Decreases linearly

Description : With increase in absolute humidity, the dew point of an unsaturated mixture of air and water vapor (at constant pressure and temperature). (A) Increases (B) Remains unchanged (C) Decreases (D) Decreases linearly

Last Answer : (A) Increases

Air at a particular humidity is heated in a furnace. The new dew point (A) Decreases (B) Increases (C) Depends on the extent of heating (D) Remain unchanged

Description : Air at a particular humidity is heated in a furnace. The new dew point (A) Decreases (B) Increases (C) Depends on the extent of heating (D) Remain unchanged

Last Answer : (B) Increases

The temperature to which a vapour gas mixture must be cooled (at varying humidity) to become saturated is called the __________ temperature. (A) Dew point (B) Wet bulb (C) Dry bulb (D) None of these

Description : The temperature to which a vapour gas mixture must be cooled (at varying humidity) to become saturated is called the __________ temperature. (A) Dew point (B) Wet bulb (C) Dry bulb (D) None of these

Last Answer : (D) None of these

Air initially at 101. 3 kPa and 40°C and with a relative humidity of 50%, is cooled at constant pressure to 30°C. The cooled air has a (A) Higher dew point (B) Higher absolute (specific) humidity (C) Higher relative humidity (D) Higher wet bulb temperature

Description : Air initially at 101. 3 kPa and 40°C and with a relative humidity of 50%, is cooled at constant pressure to 30°C. The cooled air has a (A) Higher dew point (B) Higher absolute (specific) humidity (C) Higher relative humidity (D) Higher wet bulb temperature

Last Answer : (C) Higher relative humidity

An air-water vapour mixture has a dry bulb temperature of 60°C and a dew point temperature of 40°C. The total pressure is 101.3 kPa and the vapour pressure of water at 40°C and 60°C are 7.30 kPa and 19.91 kPa respectively. The humidity of air sample expressed as kg of water vapour/kg of dry air is: (A) 0.048 (B) 0.079 (C) 0.122 (D) 0.152

Description : An air-water vapour mixture has a dry bulb temperature of 60°C and a dew point temperature of 40°C. The total pressure is 101.3 kPa and the vapour pressure of water at 40°C and 60°C are 7.30 kPa and 19.91 kPa respectively ... air is: (A) 0.048 (B) 0.079 (C) 0.122 (D) 0.152

Last Answer : (D) 0.152

Dew point of an air-water vapor mixture (A) Decreases with decrease in pressure (B) At constant humidity & total pressure is fixed (C) Corresponding to any point on the humidity chart is obtained by projecting a line through this point parallel to the temperature axis and to the saturation curve (D) All 'a', 'b' & 'c'

Description : Dew point of an air-water vapor mixture (A) Decreases with decrease in pressure (B) At constant humidity & total pressure is fixed (C) Corresponding to any point on the humidity chart is obtained by projecting a ... to the temperature axis and to the saturation curve (D) All 'a', 'b' & 'c'

Last Answer : (D) All 'a', 'b' & 'c'

Unsaturated air (with dry bulb temperature and dew point being 35°C and 18°C respectively) is passed through a water spray chamber maintained at 15°C. The air will be cooled (A) And humidified (B) And dehumidified with increase in wet bulb temperature (C) At the same relative humidity (D) And dehumidified with decrease in wet bulb temperature

Description : Unsaturated air (with dry bulb temperature and dew point being 35°C and 18°C respectively) is passed through a water spray chamber maintained at 15°C. The air will be cooled (A) And ... (C) At the same relative humidity (D) And dehumidified with decrease in wet bulb temperature

Last Answer : (D) And dehumidified with decrease in wet bulb temperature

Which of the following can be calculated theoretically using steam table and Dalton's law of partial pressure; if the relative humidity and dry bulb temperature of moist air is known? (A) Dew point (B) Humidity ratio (C) Wet bulb temperature (D) None of these

Description : Which of the following can be calculated theoretically using steam table and Dalton's law of partial pressure; if the relative humidity and dry bulb temperature of moist air is known? (A) Dew point (B) Humidity ratio (C) Wet bulb temperature (D) None of these

Last Answer : (C) Wet bulb temperature

If atmospheric temperature and dew point are nearly equal, then the relative humidity is (A) Zero (B) 50% (C) Almost 100% (D) unpredictable

Description : If atmospheric temperature and dew point are nearly equal, then the relative humidity is (A) Zero (B) 50% (C) Almost 100% (D) unpredictable

Last Answer : (C) Almost 100%

When dry bulb temperature & wet bulb temperature of moist air is the same, it means that the (A) Partial pressure of water vapour is less than the total pressure (B) Humidity is < 100% & dew point temperature of air has not reached (C) Dew point temperature of air has not reached & air is not saturated fully (D) Air is fully saturated

Description : When dry bulb temperature & wet bulb temperature of moist air is the same, it means that the (A) Partial pressure of water vapour is less than the total pressure (B) Humidity is < 100% & dew ... Dew point temperature of air has not reached & air is not saturated fully (D) Air is fully saturated

Last Answer : (D) Air is fully saturated

During sensible heating of humid air (A) Relative humidity increases (B) Dew point remains constant (C) Dry bulb & wet bulb temperature increases (D) Both 'b' & 'c'

Description : During sensible heating of humid air (A) Relative humidity increases (B) Dew point remains constant (C) Dry bulb & wet bulb temperature increases (D) Both 'b' & 'c'

Last Answer : (D) Both 'b' & 'c'

Moist air is cooled along the line of constant __________ , when it is passed over a cold & dry cooling coil, such that no condensation occurs? (A) Enthalpy (B) Relative humidity (C) Wet bulb temperature (D) Dew point temperature

Description : Moist air is cooled along the line of constant __________ , when it is passed over a cold & dry cooling coil, such that no condensation occurs? (A) Enthalpy (B) Relative humidity (C) Wet bulb temperature (D) Dew point temperature

Last Answer : (D) Dew point temperature

At 100% relative humidity, the dew point temperature of moist air is (A) Less than the wet bulb temperature (B) More than the wet bulb temperature (C) Equal to the wet bulb temperature (D) Equal to the ambient temperature

Description : At 100% relative humidity, the dew point temperature of moist air is (A) Less than the wet bulb temperature (B) More than the wet bulb temperature (C) Equal to the wet bulb temperature (D) Equal to the ambient temperature

Last Answer : (B) More than the wet bulb temperature

The dew point of moist air becomes __________ with decrease in its relative humidity. (A) Less than the wet bulb temperature (B) More than the wet bulb temperature (C) More than the dry bulb temperature (D) Equal to wet bulb temperature

Description : The dew point of moist air becomes __________ with decrease in its relative humidity. (A) Less than the wet bulb temperature (B) More than the wet bulb temperature (C) More than the dry bulb temperature (D) Equal to wet bulb temperature

Last Answer : Option A

The dew point temperature lines on psychrometric charts are straight inclined sloping downwards to the right. When relative humidity of moist air is 100%, then (A) Wet bulb temperature=dry bulb temperature (B) Wet bulb temperature=dew point temperature (C) Saturation temperature=dew point temperature (D) All 'a', 'b' & 'c

Description : The dew point temperature lines on psychrometric charts are straight inclined sloping downwards to the right. When relative humidity of moist air is 100%, then (A) Wet bulb temperature=dry bulb temperature (B) ... temperature (C) Saturation temperature=dew point temperature (D) All 'a', 'b' & 'c

Last Answer : Option D

Also called absolute humidity and specific humidity.  a. Related humidity  b. Humidity ratio  c. Dew point  d. Adiabatic ratio

Description : Also called absolute humidity and specific humidity.  a. Related humidity  b. Humidity ratio  c. Dew point  d. Adiabatic ratio

Last Answer : Humidity ratio

Is define as the ratio of the actual pressure of the vapor  a. Relative Humidity  b. Humidity Ratio  c. Dew Point  d. Adiabatic Saturation

Description : Is define as the ratio of the actual pressure of the vapor  a. Relative Humidity  b. Humidity Ratio  c. Dew Point  d. Adiabatic Saturation

Last Answer : Relative Humidity

_________ is the temperature to which the air must be cooled, at constant pressure, to produce saturation.  a. relative humidity  b. triple point temperature  c. dew point  d. critical point

Description : _________ is the temperature to which the air must be cooled, at constant pressure, to produce saturation.  a. relative humidity  b. triple point temperature  c. dew point  d. critical point

Last Answer : dew point

What is Water vapour beyond the dew point? -Do You Know?

Description : What is Water vapour beyond the dew point? -Do You Know?

Last Answer : answer:

What happens its dew point as an air mass increases in temperature?

Description : What happens its dew point as an air mass increases in temperature?

Last Answer : As an air mass increases in temperature it's dew point falls(becomes a smaller number)

What would happen to the height of a cloud base if the dew point temperature or lower?

Description : What would happen to the height of a cloud base if the dew point temperature or lower?

Last Answer : Need answer

What are dew point sensors used for?

Description : What are dew point sensors used for?

Last Answer : dew point sensors are used for very accurate measurement of relative humidity and temperature and also used fot the calculation of dewpoint temperature and absolute humidity.

What has to happen for Condensation to occur in nature air must be cooled to its dew point and there must be some kind of solid surface present true or false?

Description : What has to happen for Condensation to occur in nature air must be cooled to its dew point and there must be some kind of solid surface present true or false?

Last Answer : 1

What relationship would you expect to find between the air temperature and dew point temperature at ground level if an area is covered in fog?

Description : What relationship would you expect to find between the air temperature and dew point temperature at ground level if an area is covered in fog?

Last Answer : The relationship that you expect to find between the air temperature and dew point temperature at ground level if the area is covered by fog is the temperatures of th air and the dew point would be very close in value.

For the study of climate which of the following is not relevant? (a) Flash point (b) Steenson screen (c) Dew point (d) Hygrogram

Description : For the study of climate which of the following is not relevant? (a) Flash point (b) Steenson screen (c) Dew point (d) Hygrogram

Last Answer : Ans: (a)

In psychrometric chart, dew point temperature lines are A. horizontal B. vertical C. curved D. straight lines slopping downwards to the right

Description : In psychrometric chart, dew point temperature lines are A. horizontal B. vertical C. curved D. straight lines slopping downwards to the right

Last Answer : ANSWER : A

The dew point is the: a. Dry bulb temperature on a psychrometer b. Temperature at which water vapour will start to be absorbed into the air c. Temperature below which water vapour will start to condense out of the air d. Pressure below which water vapour will start to condense out of the air e. Temperature at which water will start to evaporate

Description : The dew point is the: a. Dry bulb temperature on a psychrometer b. Temperature at which water vapour will start to be absorbed into the air c. Temperature below which water vapour will start to ... vapour will start to condense out of the air e. Temperature at which water will start to evaporate

Last Answer : Answer: C

Dew point can be best defined as the: a. Absolute temperature at which air, upon heating, will evaporate moisture b. . Percentage of moisture that air can hold at a given temperature and pressure c. . Temperature that air will begin to evaporate moisture d. . Temperature at which air, upon cooling, becomes saturated, causing moisture to condense should the temperature drop further e. . Atmospheric pressure at which air will condense moisture

Description : Dew point can be best defined as the: a. Absolute temperature at which air, upon heating, will evaporate moisture b. . Percentage of moisture that air can hold at a given temperature ... to condense should the temperature drop further e. . Atmospheric pressure at which air will condense moisture

Last Answer : Answer: D

The dew point temperature is less than the wet bulb temperature for A. saturated air B. unsaturated air C. both saturated and unsaturated air D. none of the above

Description : The dew point temperature is less than the wet bulb temperature for A. saturated air B. unsaturated air C. both saturated and unsaturated air D. none of the above

Last Answer : ANSWER : B

What is the perfect condition for dehumidification of air? A. air is heated above its dew point temperature B. air is cooled up to its dew point temperature C. air is heated below its dew point temperature D. air is cooled below its dew point temperature

Description : What is the perfect condition for dehumidification of air? A. air is heated above its dew point temperature B. air is cooled up to its dew point temperature C. air is heated below its dew point temperature D. air is cooled below its dew point temperature

Last Answer : ANSWER : D

A Mixture of dry air and water,the formation of fog starts when, A. air temperature is equal to the dew point temperature B. air temperature is greater than the dew point temperature C. both a. and b. D. none of the above

Description : A Mixture of dry air and water,the formation of fog starts when, A. air temperature is equal to the dew point temperature B. air temperature is greater than the dew point temperature C. both a. and b. D. none of the above

Last Answer : ANSWER : A

The temperature at which the air cannot hold all the water vapour mixed in it and some vapour starts condensing is called as A. humidification temperature B. dehumidification temperature C. dew point temperature D. none of the above

Description : The temperature at which the air cannot hold all the water vapour mixed in it and some vapour starts condensing is called as A. humidification temperature B. dehumidification temperature C. dew point temperature D. none of the above

Last Answer : ANSWER : C

What is the temperature at which the water vapour in the mixture of water vapour in air, starts condensing called? A. condensation temperature B. dew point temperature C. vaporization temperature D. all of the above

Description : What is the temperature at which the water vapour in the mixture of water vapour in air, starts condensing called? A. condensation temperature B. dew point temperature C. vaporization temperature D. all of the above

Last Answer : ANSWER : B

Water vapour beyond the dew point result in A. Precipitation B. Hailstorm C. Condensation D. Formation of ice

Description : Water vapour beyond the dew point result in A. Precipitation B. Hailstorm C. Condensation D. Formation of ice

Last Answer : ANSWER: C

On large generators, space heaters are used to ____________. A. keep the machine at ambient tmperature of the machinery space B. maintain rotor and stator winding temperatures above the dew point to prevent the formation of condensation C. prevent condensation in the lube oil D. prevent electrolysis due to condensation in the bearings

Description : On large generators, space heaters are used to ____________. A. keep the machine at ambient tmperature of the machinery space B. maintain rotor and stator winding temperatures above the dew point ... C. prevent condensation in the lube oil D. prevent electrolysis due to condensation in the bearings

Last Answer : Answer: B

The purpose of the 'heater resistors' for the winch circuit shown in the illustration is to _______________. EL-0102 A. limit the current in the heater circuit B. dispel moisture in the 'master switch' housing & control panel C. keep the winch brake housing below the dew point D. maintain winch motor operating temperature

Description : The purpose of the 'heater resistors' for the winch circuit shown in the illustration is to _______________. EL-0102 A. limit the current in the heater circuit B. dispel moisture in the ' ... panel C. keep the winch brake housing below the dew point D. maintain winch motor operating temperature

Last Answer : Answer: B

If the dew point is below freezing, it is referred to which point?

Description : If the dew point is below freezing, it is referred to which point?

Last Answer : Frost point

What is Water vapour beyond the dew point?

Description : What is Water vapour beyond the dew point?

Last Answer : Condensation

. The most suitable equipment for removing the fine dust particle (< 1 micron dia.) from air below its dew point will be a/an (A) Bag filter (B) Electrostatic precipitator (C) Cyclone separator (D) Wet scrubber

Description : . The most suitable equipment for removing the fine dust particle (< 1 micron dia.) from air below its dew point will be a/an (A) Bag filter (B) Electrostatic precipitator (C) Cyclone separator (D) Wet scrubber

Last Answer : (B) Electrostatic precipitator

__________ is the temperature at which a gas-vapor mixture becomes saturated, when cooled at constant total pressure out of contact with a liquid. (A) Dew point (B) Bubble point (C) Dry bulb temperature (D) Wet bulb temperature

Description : __________ is the temperature at which a gas-vapor mixture becomes saturated, when cooled at constant total pressure out of contact with a liquid. (A) Dew point (B) Bubble point (C) Dry bulb temperature (D) Wet bulb temperature

Last Answer : (A) Dew point

Dry bulb temperature of unsaturated air is more than its __________ temperature. (A) Dew point (B) Wet bulb (C) Both 'a' & 'b' (D) Neither 'a' nor 'b

Description : Dry bulb temperature of unsaturated air is more than its __________ temperature. (A) Dew point (B) Wet bulb (C) Both 'a' & 'b' (D) Neither 'a' nor 'b

Last Answer : (C) Both 'a' & 'b

A mixture of 10% C6H6 vapour in air at 25°C and 750 mm Hg has a dew point of 20°C. Its dew point at 30°C and 700 mm Hg will be around __________ °C. (A) 21.7 (B) 20 (C) 27.3 (D) 18.7

Description : A mixture of 10% C6H6 vapour in air at 25°C and 750 mm Hg has a dew point of 20°C. Its dew point at 30°C and 700 mm Hg will be around __________ °C. (A) 21.7 (B) 20 (C) 27.3 (D) 18.7

Last Answer : (D) 18.7