Unit 2 - Science for Engineering

Question 1

What are the 7 SI base unit

Answer 1

o Metre for length
o kilogram for mass
o second for time
o ampere for electric current
o kelvin for temperature
o candela for luminous intensity
o mole for amount of substance

Question 2

Define accuracy in measurement.

Answer 2

A quality denoting how close a measured value is to the true value.

Question 3

What is intrinsic error?

Answer 3

The error of a measuring instrument determined under reference conditions.

Question 4

What is precision in measurement?

Answer 4

A quality denoting the consistency of measured values obtained by repeated measurements.

Question 5

What is the formula for relative error?

Answer 5

Relative error = absolute error / true value.

Question 6

How is absolute correction calculated?

Answer 6

Absolute correction = true value - indicated value.

Question 7

What is the formula for density (p)?

Answer 7

Density (p) = mass (m) / volume (V).

Question 8

Define Newton (N) in terms of force.

Answer 8

1 N is the force required to give a mass of 1 kg an acceleration of 1 m/s².

Question 9

What is the relationship between work, force, and distance?

Answer 9

Work done = force x distance moved in the direction of the force.

Question 10

What is the SI unit of energy?

Answer 10

Joule (J).

Question 11

What does the term ‘power’ refer to in physics?

Answer 11

The rate of doing work or converting energy from one form to another.

Question 12

What is Coulomb (C) in relation to electric charge?

Answer 12

The charge that crosses a section of the circuit in 1 second when a current of 1 ampere flows.

Question 13

What is Ohm’s law?

Answer 13

The current through a conductor is proportional to the potential difference across it, provided its temperature remains constant.

Question 14

What is the formula for electrical power (P)?

Answer 14

P = W/t.

Question 15

What is the definition of resistivity (ρ)?

Answer 15

A relationship between the dimensions of a specimen of a material and its resistance.

Question 16

What does efficiency measure in a system?

Answer 16

The ratio of work output to work input.

Question 17

What is the formula for calculating the total resistance in a series circuit?

Answer 17

Total resistance = R1 + R2 + … + Rn.

Question 18

Fill in the blank: The rate of change of velocity is known as _______.

Answer 18

acceleration.

Question 19

True or False: Scalars have both direction and magnitude.

Answer 19

False.

Question 20

What is the formula for resistance (R)?

Answer 20

R = ρ(l/A)

Where ρ is resistivity, l is length, and A is cross-sectional area.

Question 21

What is the temperature coefficient of resistance?

Answer 21

It describes how the resistance of a material changes with temperature.

This is crucial for understanding the behavior of resistors under varying thermal conditions.

Question 22

What does an electric field represent?

Answer 22

A region of space where a force acts on a stationary charge.

The strength of the electric field (E) can be calculated using the formula E = V/d.

Question 23

Define capacitance (C).

Answer 23

The property of a conductor to store an electric charge, defined as the ratio of charge Q to potential V.

One farad (F) is the capacitance of a conductor at 1 volt carrying 1 coulomb.

Question 24

What is the formula for energy (W) stored in a capacitor?

Answer 24

W = 1/2 CV^2

This formula highlights the relationship between capacitance, voltage, and stored energy.

Question 25

What is a time constant (τ) in relation to a capacitor?

Answer 25

It is defined by the product of resistance (R) and capacitance (C). ## Footnote A capacitor discharges through a resistor in about 5 time constants (5τ).

Question 26

What is the formula for the discharge of a capacitor?

Answer 26

v = v0 e^(-t/RC) ## Footnote v0 is the initial potential difference, and v is the potential difference at time t.

Question 27

What is inductance (L)?

Answer 27

A measure of a coil's ability to induce an electromotive force (e.m.f.) when the current changes. ## Footnote One henry (H) is defined as the inductance that induces 1 volt when the current changes at a rate of 1 ampere per second.

Question 28

What is the formula for energy (WL) stored in a magnetic field of a coil?

Answer 28

WL = 1/2 LI^2 ## Footnote L is inductance and I is the current through the coil.

Question 29

Define ductility.

Answer 29

The ability of a material to plastically deform without breaking, such as being drawn into wires.

Question 30

What is brittleness?

Answer 30

The tendency of materials to break without undergoing any plastic deformation.

Question 31

What does toughness measure?

Answer 31

The amount of energy stored in a material before failure.

Question 32

What is the elastic limit?

Answer 32

The maximum stress that can be applied without permanently deforming the material.

Question 33

What is Hooke's Law?

Answer 33

States that the force (F) applied to a spring is directly proportional to the extension (x) of the spring, F = kx.

Question 34

What is the difference between elastic and plastic deformation?

Answer 34

Elastic deformation is reversible, while plastic deformation is permanent.

Question 35

How is strain energy calculated from a force-extension graph?

Answer 35

It is equal to the area under the force-extension graph.

Question 36

What is ultimate tensile stress?

Answer 36

The maximum stress that can be applied to a material before it breaks.

Question 37

What is gauge pressure?

Answer 37

The pressure indicated on a gauge above atmospheric pressure.

Question 38

What does Archimedes' principle state?

Answer 38

The up-thrust force acting on an immersed object is equal to the weight of the fluid displaced.

Question 39

Define viscosity.

Answer 39

The fluid's ability to resist shear forces.

Question 40

What is the non-flow energy equation?

Answer 40

U1 + Q = U2 + W ## Footnote Where U is internal energy, Q is heat energy, and W is work done.

Question 41

What is the steady flow energy equation?

Answer 41

Q = (W2 - W1) + W ## Footnote This equation relates heat energy supplied to the work done by the system.

Question 42

What is the internal energy of a system?

Answer 42

The sum of the random distribution of kinetic and potential energy of the molecules.

Question 43

What does the thermodynamic scale refer to?

Answer 43

A scale used to measure temperature, where absolute zero is the theoretical point at which molecular motion stops.

Question 44

What is the internal energy of a system?

Answer 44

The sum of a random distribution of kinetic and potential energy concerned with the molecules of the system.

Question 45

What is the thermodynamic scale?

Answer 45

A scale measuring temperature, where on the Kelvin scale, absolute zero is the temperature at which all substances have a minimum internal energy.

Question 46

What is Boyle’s law?

Answer 46

A gas law stating that pressure and volume of a gas are inversely proportional at constant temperature.

Question 47

What is the equation for Boyle’s law?

Answer 47

pV = C (constant) or p1V1 = p2V2.

Question 48

What is Charles’ law?

Answer 48

A gas law stating that the volume of a gas is directly proportional to its temperature at constant pressure.

Question 49

What is the equation for Charles’ law?

Answer 49

V = C (constant) or V1/T1 = V2/T2.

Question 50

What is the Pressure law?

Answer 50

A gas law stating that the pressure of a gas is directly proportional to its temperature at constant volume.

Question 51

What is the equation for the Pressure law?

Answer 51

p = C (constant) or p1/T1 = p2/T2.

Question 52

What is the Combined gas law?

Answer 52

A gas law that combines Boyle's, Charles', and the Pressure law.

Question 53

What is the equation for the Combined gas law?

Answer 53

p1V1/T1 = p2V2/T2.

Question 54

What is the Ideal gas equation?

Answer 54

pV = nRT, where n is the number of moles and R is the molar gas constant.

Question 55

What is the characteristic gas equation?

Answer 55

pV = mRT, where m is the mass of the gas and R is the specific gas constant for that gas.

Question 56

What is specific heat capacity?

Answer 56

The energy required to raise the temperature of 1 kg of a material by 1°C.

Question 57

What is the formula for heat energy (sensible heat)?

Answer 57

Q = mcΔT.

Question 58

What is the efficiency equation?

Answer 58

η = work output / work input.

Question 59

What is sensible heat?

Answer 59

Heat energy which results in a change of temperature.

Question 60

What is latent heat?

Answer 60

Heat energy absorbed or emitted during a change of state.

Question 61

What is specific latent heat?

Answer 61

The energy change resulting in the change of state of 1 kg of substance.

Question 62

What is the formula for latent heat?

Answer 62

Q = mL.