Chapter 1- Physical Quantities, Units & Measurements

Question 0

Mega prefix and multiplying factor

Answer 0

1000000 or 10 to power 6

Question 1

Giga prefix and multiplying factor

Answer 1

1000000000 or 10 to power 9

Question 2

Kilo prefix and multiplying factor

Answer 2

1000 or 10 to power 3

Question 3

Deci prefix and multiplying factor

Answer 3

0.1(1/10) or 10 to power -1

Question 4

Centi prefix and multiplying factor

Answer 4

0.01(1/100) or 10 to power -2

Question 5

Milli prefix and multiplying factor

Answer 5

0.001(1/1000) or 10 to power -3

Question 6

Micro prefix and multiplying factor

Answer 6

1/1000000 or 10 to power -6

Question 7

Nano prefix and multiplying factor

Answer 7

1/1000000000 or 10 to power -9

Question 8

Measuring tape range and precision

Answer 8

0-5m and 0.1 cm

Question 9

Metre rule range and precision

Answer 9

0-1m and 0.1 cm

Question 10

Vernier caliper range and precision

Answer 10

0-15cm and 0.01cm

Question 11

Micrometer screw gauge range and precision

Answer 11

0-2.5cm and 0.01mm or 0.001cm

Question 12

Measuring tapes and rules- things to keep in mind

Answer 12

• eye must be positioned so that line of sight is at right angle to scale
• this avoids parallax error, which may be due to incorrect positioning of eye
• Parallax error may also be due to object not being on same level as markings on scale

Question 13

Vernier calipers- what to keep in mind

Answer 13

Compensate for any zero error present

Question 14

Micrometer screw gauge- things to keep in mind

Answer 14

Grip object between anvil and spindle by turning the ratchet to prevent over-tightening and to ensure identical pressure applied on the object.

Compensate for any zero error present

Question 15

Random errors

Answer 15

• occurs inconsistently
• can be caused by inaccurate reading of an observer from a scale (eg parallax error, human judgement error etc)
• or due to background disturbance (eg wind, background noise, vibration in the environment)
• Cause poor precision
• can be reduced by averaging the results of repeated measurements

Question 16

Systematic errors

Answer 16

• occurs consistently
• can be caused by zero error or instrument being incorrectly calibrated
• can be detected by comparing with a calibration standard
• can cause poor accuracy in measurement
• can be adjusted applying correct factor

Question 17

Precision and random errors

Answer 17

Precision indicates the size of random errors in a set of measurements or how close the readings are to average value

Question 18

Accuracy and systematic errors

Answer 18

Accuracy indicates the size of systematic errors in a set of measurements or how close the readings are to true value

Question 19

State what is meant by scalar quantities

Answer 19

Scalar quantities are quantities that have magnitude only

Question 20

Examples of scalars

Answer 20

Distance 
Speed 
Mass 
Time 
Pressure 
energy 
Temperature

Question 21

SI Base units (length, mass and time)

Answer 21

Length: metre
Mass: kilogram
Time: second

Question 22

Volume

Answer 22

Cubic meter (m^3)

Question 23

Density

Answer 23

Kilogram per cubic metre (kg m-3)

Question 24

Velocity

Answer 24

Metre per second (m s-1)

Question 25

Acceleration

Answer 25

Mature per second squared (ms-2)

Question 26

Force

Answer 26

Newton (N), m kg s-2

Question 27

Energy and work

Answer 27

Joule (J), m2 kg s-2

Question 28

Power

Answer 28

Watt (W), m2 kg s-3

Question 29

Plot a graph of zebras against grass

Answer 29

Vertical axis: zebras

Horizontal axis: grass

Question 30

Frequency

Answer 30

Hertz (Hz), s-1