Question 1

Which of these equals one standard atmosphere at sea level? A)1.01325 x 10⁵ N/m² B)1 x 10⁵ Pascal's, Pa C)1 x 10⁴ N/m² D)30 m H₂O E)1013.25 mm Hg

Accepted Answer

E  1 standard atmosphere is equivalent to 1.01325 x 10^5 N/m^2 and 1013.25 mm Hg.

Question 2

Which is the Specific Heat Capacity of air?
A)Sensible heat content kJ/kg
B)1.012 kJ/kg K
C)Total heat content kJ/kg
D)1.205 kJ/kg
E)4.186 kJ/kg K

Accepted Answer

Specific Heat Capacity is defined as the amount of heat required to raise the temperature of a substance by 1 degree Celsius. The Specific Heat Capacity of dry air at constant pressure and room temperature is approximately 1.012 kJ/kg K.

Question 3

Which is correct about the density of humid air? A)0.802 m³/kg B)4.186 kg/m3 at 21^oC, 60% relative humidity C)1.013 kg/m3 at 20^oC, sea level D)1.205 kg/m3 at 20^oC, 1013.25 mb E)5.67 kg/m³

Accepted Answer

The density of dry air at 20°C and 1013.25 mb (standard atmospheric pressure at sea level) is approximately 1.205 kg/m³. This value is a standard reference for air density under these conditions.

Question 4

Which is correct about the density of water? A)1.2 x 10³ kg/m³ B)1 g/cm³ C)1 kg per litre D)Specific gravity is 4.186 E)1000 tonne/m³ at 10^oC

Accepted Answer

The answer of Which is correct about the density of...

Question 5

Which of these has the correct units? A)1 Joule = 1 N/m² B)1 Joule = 1 kg x 1 m C)1 Watt = 1 kg x g m/s² D)10³ Joules = 3600 kN/m² E)1 Newton = 1 kg x 1 m/²

Accepted Answer

1 Newton is defined as the force required to accelerate 1 kilogram of mass at the rate of 1 meter per second squared, hence the correct unit is $1 \, \text{N} = 1 \, \text{kg} \cdot 1 \, \text{m/s}^2$.

Question 6

Which of these has the correct electrical units? A)Electrical energy meters accumulate kW/h B)1 MW =10³ W C)10³ kJ = 10³ kW/s D)1 Watt = 1 volt x 1 ampere E)10³ W = 10³ V x 10³ A

Accepted Answer

Electrical power is the product of voltage and current (P=VI). Therefore, 1 Watt, which is the unit of power, can be expressed as 1 volt multiplied by 1 ampere, the units of voltage and current respectively. The other options contain incorrect units or incorrect conversions between units.

Question 7

Which of these has the correct pressure units? A)1 b = 10⁵ N/m² B)1.01325 mb = 1 atmosphere C)1 MN = 10³ kN/m² D)1 b = 1 kN/m² E)13.6 mb = 13.6 N/m²

Accepted Answer

The answer of Which of these has the correct pressure...

Question 8

Which has the correct meaning for frequency?
A)Alternating current rate of increase
B)Revolutions per minute
C)Electrical single or three phase
D)Torque of a motor
E)Air changes per hour

Accepted Answer

Frequency refers to the number of cycles or revolutions per unit of time, usually measured in Hertz (Hz), which is equivalent to one cycle per second. Revolutions per minute (RPM) is a common unit for measuring frequency, especially in the context of rotating machinery.

Question 9

Which is correct about Kelvin? A)Degrees measured above absolute zero at -180^oF B)Name of a famous Scottish scientist who invented the steam engine. C)Invented first bicycle in Scotland D)Kelvin McAdam invented tarmacadam for road surfacing E)K = C + 273

Accepted Answer

Kelvin is a unit of temperature, and it equals Celsius + 273. Option A is partially correct, but the temperature scale starts at absolute zero, not -180^oF. Options B, C, and D are incorrect as they refer to different people and inventions.

Question 10

A room 12 m long, 8 m wide and having an average height of 4 m, has a volume of which? A)384 m³ B)400 m³ C)62 m³ D)462 m³ E)3840 litre

Accepted Answer

The volume of the room is calculated by multiplying its length, width, and height: 12 m * 8 m * 4 m = 384 m^3.

Quiz 14: Understanding Units

Which of these equals one standard atmosphere at sea level?

Which is the Specific Heat Capacity of air?

Which is correct about the density of humid air?

Which is correct about the density of water?

Which of these has the correct units?

Which of these has the correct electrical units?

Which of these has the correct pressure units?

Which has the correct meaning for frequency?

Which is correct about Kelvin?

A room 12 m long, 8 m wide and having an average height of 4 m, has a volume of which?