Page 10 - 9-phy-1 Physical Quantities and Measurements

1. Physical Quantities and Measurements eLearn.Punjab

These prefixes are given in Table 1.3. The prefixes are useful Table 1.3: Some Prefixes
to express very large or small quantities. For example, divide
20,000 g by 1000 to express it into kilogramme, since kilo Prefix Symbol Multiplier
represents 103 or 1000.
exa E 1018
Table 1.4 shows some multiples and sub-multiples of length. peta P 1015
However, double prefixes are not used. For example, no prefix tera T 1012
is used with kilogramme since it already contains the prefix giga G 109
kilo. mega M 106
kilo k 103
Prefixes given in Table 1.3 are used with both types base and hecto h 102
derived units. Let us consider few more examples: deca da 101
deci d 10-1
centi c 10-2
milli m 10-3
micro µ 10-6
nano n 10-9
pico p 10-12
femto f 10-15

atto a 10-18

(i) 200 000 ms-1 = 200 x 103ms-1 = 200kms-1

(ii) 4800 000W = 4800 x 103 W = 4800 kW

= 4.8 x 106 W = 4.8 MW

(iii) 3300 000 000 Hz = 3300 x 106 Hz = 3300 MHz

= 3.3x103 MHz = 3.3 Ghz

(iv) 0.00002 g = 0.02 x 10-3g = 20 x 10-6g
= 20 µg

(v) 0.000 000 0081m = 0.0081 x 10-6m = 8.1x10-9m

= 8.1 nm

Table 1.4: Multiples and

sub-multiples of length

1 km 103 m

1 cm 10-2 m

1 mm 10-3 m

1 µm 10-6 m

1 nm 10-9 m

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