PHYSICS SPM

Form 5Chapter 1: WavesChapter 1: ElectricChapter 1: ElectromagnetChapter 1: ElectronicChapter 1: Radioactive

Form 4Chapter 1: Intro. to physicsChapter 2: Force & motionChapter 3: Force & pressureChapter 4: HeatChapter 5: Light

Vernier caliper(± 0.01 cm)

+ zero error - zero error

+ 0.08 cm - 0.01 cm

2.47 cm

Micrometer screw gauge(± 0.01 mm)

7.37 mm

+ zero error - zero error

+ 0.09 mm - 0.04 mm

MEASUREMENT

AccuracyThe closeness of a measurement to the actual value

ConsistencyThe ability of a

measuring instrument to

measure with little deviation in the measurements

SensitivityThe ability of a

measuring instrument to detect a small change in the

measurements

ERROR

Systematic errorDue to:Instrument

Example:Zero errorAbsolute error (error in calibration)

Random errorDue to:Human mistakes Surrounding factor

Example:Parallax error

Motion graph

Mercury Barometer

Pressure at P = 0 cm HgQ = 76

cm Hg R =

91 cm Hg S =

106 cm Hg

Pressure at P = 20 cm HgQ = 76

cm Hg R =

91 cm Hg S =

106 cm Hg

[Atmospheric pressure is 76 cm Hg ][Mercury density = 1.36 x 104 kg m–3]

U-tube manometer

Pgas = Pwater= (h ρ g)

= (1000)(10)(0.1)= 1000 Pa

[Density of water = 1 000 kg m-3]

Pgas = Patm + Pwater= Patm + (h ρ g)

= (1x105)+1000 Pa= 1.01x105 Pa

[Atmospheric pressure is 1x105 Pa]

U-tube manometer

Pressure at A = Pressure at BPatm + hoil ρoil goil = Patm + hwater ρwater

gwater

hoil ρoil goil = hwater ρwater gwater

ρoil = (10)(1) ÷ (12) = 0.83 g cm-3

Density of water = 1 g cm-3

What is the density of the oil ?

Pair + Pmercury = PatmPair + 10 cmHg = 76cmHgPair = (76 – 10) cmHg

= 66 cmHg

Densities of liquid M = 1000kgm-3

Densities of liquid N = 2500kgm-3

What is the pressure ofa. liquid M at point xb. liquid M and N at point y

P= ρgh= (1000)(10)(0.5)= 5 kPa

P= (ρgh)M + (ρgh)N

= (1000)(10)(0.5) + (2500)(10)(0.3)= 5 kPa + 7.5 kPa= 12.5 kPa

Pressure in tube

atmospheric pressure is 76 cm Hg.What is the pressure of the trapped air P ?

P1 = P2

F Bouyant = W liquid displaced

F Bouyant = W liquid displaced = W object

V ↑ P↓V ↓ P↑

Characteristic at thermal equilibrium:

1. Temperature A = Temperature B

2. Net rate of heat transfer = 0( Rate of heat transfer from A to B = Rate of heat transfer from B to A

GAS LAW

PT

V

1.

2.

3.

CONVERGING DIVERGING

LENS convex concave

MIRROR concave convex

LENSES & MIRROR

CONVEX MIRROR &

CONCAVE LENS

u anywhereVIRTUAL

UPRIGHT

DIMINISHED

CHARACTERISTIC OF IMAGE

CONCAVE MIRROR

Ray P parallel - F

Ray F F - parallel

Ray C head (object / arrow) – C

REFLECTION

REFRACTIONCONVEX LENS

Ray P parallel - F

Ray F F - parallel

Ray C through centre