Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice physics heat and energy

Energy-related $CO _2$ accounts for approximately what share of total U.S. human-made greenhouse gases?

  1. $20%$

  2. $40%$

  3. $60%$

  4. $80%$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

These emissionsmostly from burning coal, oil, and natural gasaccounted for 82 percent of all U.S. greenhouse gases in 2013.

Multiple choice physics heat and energy

Temperature of earth's atmosphere in absence of green house gases in it:

  1. remain constant

  2. increased

  3. decreased

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The green house gases absorb some of  the radiation (which is reflected by earth, clouds etc.) and the rest is passed into space. Due to that absorbed radiation, earth's atmosphere remains warm. If green house gases would absent, no radiation will stay on earth's atmosphere and temperature of atmosphere will go fall to approx. $-18^{o}C$ which will freeze all the water on earth. 

Multiple choice dew point and humidity heat physics

The most comfortable value for Relative Humidity is

  1. 10%

  2. 20%

  3. 50%

  4. 90%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

50% 

because in this case it won't be too dry or wont be too wet.

Multiple choice dew point and humidity heat physics

The most comfortable value for RH is ______.

  1. 10%

  2. 30%

  3. 50%

  4. 90%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The most comfortable of RH is 50%,because of this value many environmental
problems can be reduced which include
Mildew
Mold
Bacteria
Condensation
Multiple choice dew point and humidity heat physics

At dew point. Relative Humidity is

  1. 10%

  2. 20%

  3. 50%

  4. 100%
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Dew point is when air gets saturated i.e RH =100%

Multiple choice dew point and humidity heat physics

If RH is high:

  1. we feel sultry

  2. we perspire less

  3. clothes do not dry easily

  4. all the above are correct
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
If the air is at 100 percent relative humidity, sweat will not evaporate into the air. As a result, we feel much hotter than the actual temperature when the relative humidity is high.
Multiple choice dew point and humidity heat physics

The units of Relative Humidity are

  1. $kg-m^{3}$

  2. kg

  3. $kg-m^{2}$

  4. none of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Relative humidity refers to the ratio of the amount of moisture in the air at a certain temperature to the maximum amount of moisture that the air can retain at the same temperature. Relative humidity is expressed as a percentage and is highest during rain.

Multiple choice dew point and humidity heat physics

Write the correct alternatives :
The vapour content in the air is measured using  a physical quantity called...............

  1. Absolute humidity

  2. Relative humidity

  3. Dew point

  4. Humidity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Relative humidity :

The ratio of the amount of water vapour actually present in the air to the greatest amount possible at the same temperature.
$\therefore$ option $"B"$ is correct.

Multiple choice dew point and humidity heat physics

When it is raining, the dew point is

  1. $0^\circ C$

  2. $50^\circ C$

  3. $100^\circ C$

  4. room temperature
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
When it is raining, the dew point is room temperature.
The dew point is the temperature at which air can hold the amount of mixture present in atmosphere. If the temperature falls below it, some water vapour must condense.
Multiple choice dew point and humidity heat physics

When the room temperature becomes equal to the dew point, the relative humidity of the room is

  1. $100$%

  2. Zero%

  3. $70$%

  4. $85$%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Relative humidity is the ratio of water vapor pressure and saturation vapor pressure at the present temperature.
When the room temperature becomes equal to the dew point, then the air is saturated. Hence the relative humidity of room is $100$ %.