Units and Dimensions: A Comprehensive Guide for Thermodynamics

Question 1

Which of the following is NOT a base unit in the International System of Units (SI)?

Accepted Answer

Horsepower

Answer

Ampere

Answer

Second

Answer

Kilogram

Question 2

Which of the following is the correct dimension for pressure?

Accepted Answer

ML^-1T^-2

Answer

L^-2T^2

Answer

MT^2

Answer

MLT^-2

Question 3

Which of the following is a dimensionless quantity?

Accepted Answer

Efficiency

Answer

Temperature

Answer

Pressure

Answer

Mass

Question 4

What is the SI unit for energy?

Accepted Answer

Joule

Answer

Newton

Answer

Calorie

Answer

Watt

Question 5

Which of the following quantities has a dimension of L^3?

Accepted Answer

Volume

Answer

Acceleration

Answer

Mass

Question 6

Which of the following is the SI unit of force?

Accepted Answer

newton (N)

Answer

watt (W)

Answer

pascal (Pa)

Answer

joule (J)

Question 7

Convert 5 inches to meters using the appropriate conversion factor:

Accepted Answer

0.127 m

Answer

508 cm

Answer

127 mm

Answer

2.54 m

Question 8

Determine the dimensions of specific heat capacity in the form of [Energy]/[Mass][Temperature]:

Accepted Answer

[Energy]/[Mass][Temperature]

Answer

[Force]/[Length][Time]

Answer

[Energy]/[Temperature]

Answer

[Energy]/[Time]

Question 9

The Buckingham Pi theorem states that the number of dimensionless groups formed from a set of variables is equal to:

Accepted Answer

the number of fundamental dimensions minus the number of variables

Answer

the number of variables

Question 10

Identify the common engineering system of units that employs feet, pounds, and seconds as its base units:

Accepted Answer

FPS system

Answer

mks system

Answer

MKS system

Answer

cgs system

Question 11

Which of the following is the SI base unit for mass?

Accepted Answer

kilogram (kg)

Answer

ounce (oz)

Answer

pound (lb)

Answer

slug

Question 12

A force of 10 newtons is applied to a 2 kilogram object. What is the acceleration experienced by the object?

Accepted Answer

5 m/s²

Answer

10 m/s²

Answer

2 m/s²

Answer

20 m/s²

Question 13

Which of the following is NOT a derived unit in SI?

Accepted Answer

meter (m)

Answer

watt (W)

Answer

pascal (Pa)

Answer

joule (J)

Question 14

The SI unit of density, defined as mass per unit volume, is:

Accepted Answer

kilogram per cubic meter (kg/m³)

Answer

pound per gallon (lb/gal)

Answer

gram per cubic centimeter (g/cm³)

Answer

slug per cubic foot (slug/ft³)

Question 15

The pressure exerted by a fluid depends on:

Accepted Answer

its density and the depth of immersion

Answer

its velocity and the depth of immersion

Answer

its velocity and the surface area of the fluid

Answer

its density and the surface area of the fluid

Question 16

A heat transfer rate of 1000 watts is equivalent to:

Accepted Answer

1 kilowatt (kW)

Answer

100 watts (W)

Answer

1 megawatt (MW)

Answer

0.1 kilowatt (kW)

Question 17

The SI unit for thermal conductivity is:

Accepted Answer

watt per meter-kelvin (W/m-K)

Answer

joule per second-meter (J/s-m)

Answer

kilocalorie per hour-meter-kelvin (kcal/h-m-K)

Answer

british thermal unit per hour-foot-fahrenheit (Btu/h-ft-°F)

Question 18

Which dimensionless group characterizes fluid flow in pipes?

Accepted Answer

Reynolds number

Answer

Nusselt number

Answer

Grashof number

Answer

Prandtl number

Question 19

The base unit of mass in the SI system is the:

Accepted Answer

kilogram (kg)

Answer

ounce (oz)

Answer

gram (g)

Answer

pound (lb)

Question 20

What is the dimensional formula for force in terms of the base SI units mass (M), length (L), and time (T)?

Accepted Answer

MLT⁻²

Answer

ML⁻¹T²

Answer

ML²T⁻²

Answer

MT²L⁻¹

Question 21

Which conversion factor is correct for converting feet (ft) to meters (m)?

Accepted Answer

1 ft = 0.3048 m

Answer

1 m = 3.281 ft

Answer

1 ft = 0.254 m

Answer

1 m = 2.54 ft

Question 22

What is the approximate value of the acceleration due to gravity (g) in SI units (meters per second squared)?

Accepted Answer

9.81 m/s²

Answer

10.0 m/s²

Answer

32.2 ft/s²

Answer

9.81 ft/s²

Question 23

Which of the following is NOT a unit of energy?

Accepted Answer

Pascal (Pa)

Answer

Calorie (cal)

Answer

British thermal unit (Btu)

Answer

Joule (J)

Question 24

What is the SI unit of pressure?

Accepted Answer

Pascal (Pa)

Answer

bar

Answer

atmosphere (atm)

Answer

torr

Question 25

Which of the following is a dimensionless quantity (has no units)?

Accepted Answer

efficiency

Answer

temperature

Answer

pressure

Answer

volume

Question 26

Which temperature scale is an absolute scale, meaning it starts at absolute zero and has no negative values?

Accepted Answer

Kelvin (K)

Answer

Celsius (°C)

Answer

Fahrenheit (°F)

Answer

Rankine (°R)

Question 27

How do you convert a temperature from degrees Celsius (°C) to Kelvin (K)?

Accepted Answer

°C + 273.15 = K

Answer

K + 273.15 = °C

Answer

°C - 273.15 = K

Answer

K - 273.15 = °C