[PHY] Chapter 1 - Measurements

DARRELL ER (COPYRIGHTED) TOPIC 1: MEASUREMENTS DARRELL ER (COPYRIGHTED) ©

CHAPTER ANALYSIS THE ABOUT TIME EXAM WEIGHTAGE DARRELL ER (COPYRIGHTED) ©

SI UNITS BASICS Base Quantity Symbol SI Unit Symbol for SI Unit Length l metre m Mass m kilogram kg Time t second s Temperature T Kelvin K Electric current ampere A Amount of substance n mole mol Capital ‘K’* *Small ‘k’ is prefix for kilo More for chemistry DARRELL ER (COPYRIGHTED) ©

PREFIXES BASICS Base Quantity Symbol Magnitude Numerical Giga G 109 1 000 000 000 Mega M 106 1 000 000 kilo k 103 1 000 deci d 10-1 ÷ 10 centi c 10-2 ÷ 100 milli m 10-3 ÷ 1 000 micro μ 10-6 ÷ 1 000 000 nano n 10-9 ÷ 1 000 000 000 (small ‘k’) (not u) How to ‘remember’ Game apps are ‘GB’ Pictures are in ‘MB’ Rice is in ‘kg’ 1 ‘deci’mal point 1cm = ÷100 of 1m 1mm = ÷10 of 1cm ‘micro’scope (small particle) Ironman suit is ‘nano’-tech, really tiny particles *Tip: Increase by ^3 Standard form: a x 10n For eg, 73000 = 7.3 x 104 DARRELL ER (COPYRIGHTED) ©

TWO PHYSICAL QUANTITIES SCALAR QUANTITIES VECTOR QUANTITIES KEY CONCEPT DARRELL ER (COPYRIGHTED) ©

SCALAR QUANTITY VECTOR QUANTITY Examples: Distance Speed Time Mass Volume Density Energy Pressure Examples: Displacement Velocity Acceleration Weight Force *To learn more in next chapter, ‘Kinematics’ DARRELL ER (COPYRIGHTED) ©

VECTOR QUANTITY Examples: Displacement Velocity Acceleration Weight Force Don’t worry too much, you will have a E-math chapter dedicated to this! DARRELL ER (COPYRIGHTED) ©

TWO INSTRUMENTS VERNIER CALIPER MICROMETER SCREW GAUGE KEY CONCEPT DARRELL ER (COPYRIGHTED) ©

How to correct zero error No zero error if the ‘0’ on both the main scale and the vernier scale is aligned. When the vernier caliper is fully closed, there is an excess of +0.01cm. Hence, this a positive zero error. When the vernier caliper is fully closed, there is a negative value of -0.02cm. Hence, this a negative zero error. To rectify any zero error, Measurement – (zero error) = actual value VERNIER CALIPER For negative zero error, read from the back. Zero error here is not 0.08cm, but -0.02cm. DARRELL ER (COPYRIGHTED) © 3.34 cm

How to correct zero error No zero error if the ‘0’ on both the main scale and the thimble scale is aligned. When the micrometer is fully closed, there is an excess of +0.02mm. Hence, this a positive zero error. When the micrometer is fully closed, there is a value of -0.04mm. Hence, this a negative zero error. To rectify any zero error, Measurement – (zero error) = actual value MICROMETER SCREW GAUGE For negative zero error, read from the back. Zero error here is not 0.46mm, but -0.04mm. DARRELL ER (COPYRIGHTED) ©