Chapter 1 Physical Quantities And Measurements 252n1o

Measurement of length SI Units: metres Symbol: m Negative Zero Error(Vernier Caliper) = Add this error to reading. Before any measurement,there is already some measurement LESS Positive Zero Error(Vernier Caliper) = Subtract this error from reading. Before any measurement,there is already some measurements MORE

Measuring Tape = 0-10m Accuracy: 0.1cm/1mm Metre Rule = 0cm-100cm Accuracy: 0.1cm/1mm Vernier Calipers = 2cm-10cm/20mm-100mm --> 2cm10cm/20mm-100mm cm: 2dp mm: 1dp Main Scale + Vernier Scale = Reading

Zero Error

Micrometer Screw Gauge = Less Than 3 cm (0-30mm) Accuracy: 0.001cm/0.01mm Sleeve + Thimble = Reading

Positive Zero Error(Micrometer) = The zero marking on the thimble scale is below the datum line. Subtract the error from the reading Negative Zero Error(Micrometer) = The zero marking on the thimble scale is above the datum line. Add the error into the reading

SI: seconds Symbol: s

Measurement of Time

Chapter 1: Physical Quantities and Measurements Physical Quantities

Clocks = Accuracy: 1 second

Quantities that can be measured and they consist of a numberical magnitude/number and a unit

Stopwatches = Electronic stopwatches time accurate : 2dp 0.01second(digital) 0.1second(analog) Same distance between 2 dots = CONSTANT Speed Increasing distance between 2 dots = INCREASING Speed Decreasing distance between 2 dots = DECREASING Speed Average speed of object, v=d/t

Ticker Tape Timer->Produces Dots(Electricity Operated) = 0.02second between 2 dots Frequency: Number of dots produced in 1 second

Defined as the time for one full oscillation to happen Defined as the number of complete oscillation in 1 second

Basic Quantities:

Used to express physical quantities that are either very LARGE or very SMALL

Length =SI: metre/meter Symbol: m

Based on the SI unit of a particular physical quantity Mass = SI: kilograms Symbol: kg

Things that move around in a manner that repeats itself A full oscillation happens when example a fan turns from left to right and back to left again

Prefixes

LARGER Units :

Periodic Motion Oscillation Period

Prefix --> Non-prefix = Multiple

Giga = Symbol: G (10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10) [ 9 ]

Non-prefix --> Prefix = Divide

Mega = Symbol: M (10 x 10 x 10 x 10 x 10 x 10) [6] SMALLER Units :

Frequency

Pendulum

Frequency (Symbol: f) f = 1/T Hz (Hertz)

Amount of substance = SI: mole Symbol: mol

kilo = Symbol: kg (10 x 10 x 10) [3]

centi = Symbol: c (1/10 x 10) milli = Symbol: m (1/10 x 10 x 10) micro = Symbol: µ (1/10 x 10 x 10 x 10 x 10 x 10)

1. Start the stopwatch only after a few oscillations 2. Measure the time taken for 20 complete oscillations and take the average 3. Ensure that the pendulum bob is displaced from the vertical at a small angle (<10 degree)

Electrical current = SI: ampere Symbol: A Temperature = SI: kelvin Symbol: K

deci = Symbol: d (1/10) The time taken for one complete oscillation ( Symbol: T)

Time = SI: kilograms Symbol: kg

Measure the period of a pendulum acurrately:

nano = Symbol: n (1/10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10) [9]

Luminous Intensity = SI: candela Symbol: cd