RRB ALP & Technician Basic science and engineering | A unit of measurement is a standardised quantity of a physical property, used as a factor to express occurring quantities of that property.

Part A

Section –Basic science and engineering
No. Of Question- 40
Marks- 40

There are seven basic units of science, i.e. KG,M,S,A,K,Mol,Cd 

kilogram (kg)– Unit of measurement of mass

metre (m)– Unit of measurement of length

second (s)- Unit of measurement of time

ampere (A)– Unit of measurement of electric current

kelvin (K)- Unit of measurement of thermodynamic temperature

mole (mol)- Unit of measurement of amount of substance

candela (cd)-Unit of measurement of luminous intensity

Length

1 m = 100 cm

1 km = 1,000 m

1 in (inch) = 2.54 cm

1 m = 39.37 in

1 mile = 5,280 ft = 1.609 km

1 angstrom = 10^–10m

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Mass

1 kg = 1,000 g

1 slug = 14.59 kg

1 u (atomic mass unit) = 1.6605 x 10^–27kg

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Force

1 lb (pound) = 4.448 N

1 N = 10⁵dynes

1 N = 0.2248 lb

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Energy

1 J = 10⁷ergs

1 J = 0.7376 ft-lb

1 BTU (British thermal unit) = 1,055 J

1 kWh (kilowatt hour) = 3.600 x 10⁶J

1 eV (electron volt) = 1.602 x 10^–19J

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Power

1 hp (horsepower) = 550 ft-lb/s

1 W (watt) = 0.7376 ft-lb/s

Length = Meter (m) 

Mass = Kilogram (kg) 

Time = Second (s) 

Electric current = Ampere (A)

Temperature =  Kelvin (K) 

Amount of a Substance = Mole (mol)

Luminous Intensity = candela (cd)

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Some measurements and their value

1 m = 100 cm = 1,000 mm (millimeters)

1 km (kilometer) = 1,000 m

1 kg (kilogram) = 1,000 g (grams)

1 N (newton) = 10⁵dynes

1 J (joule) = 10⁷ergs

1 P (pascal) = 10 Ba

1 A (amp) = 0.1 Bi

1 T (tesla) = 10⁴G (gauss)

1 C (coulomb) = 2.9979 x 10⁹Fr

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 Prefixes  – from 10^-15 to 10¹⁵ 

Femto– 10^-15   

Pico– 10 ^-12

Nano– 10^-9

Micro– 10^-6

Milli– 10^-3

Centi– 10^-2

Deci– 10^-1

Deka– 10¹

Hecto– 10²

Kilo– 10³

Mega– 10⁶

Giga– 10⁹

Tera– 10¹²

Peta – 10¹⁵

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Named units derived from SI base units

hertz	Hz	frequency	1/s	s−1
radian	rad	angle	m/m	1
steradian	sr	solid angle	m2/m2	1
newton	N	force, weight	kg⋅m/s2	kg⋅m⋅s−2
pascal	Pa	pressure, stress	N/m2	kg⋅m−1⋅s−2
joule	J	energy, work, heat	N⋅m  C⋅V  W⋅s	kg⋅m2⋅s−2
watt	W	power, radiant flux	J/s  V⋅A	kg⋅m2⋅s−3
coulomb	C	electric charge or quantity of electricity	s⋅A  F⋅V	s⋅A
volt	V	voltage, electrical potential difference, electromotive force	W/A  J/C	kg⋅m2⋅s−3⋅A−1
farad	F	electrical capacitance	C/V  s/Ω	kg−1⋅m−2⋅s4⋅A2
ohm	Ω	electrical resistance, impedance, reactance	1/S  V/A	kg⋅m2⋅s−3⋅A−2
siemens	S	electrical conductance	1/Ω  A/V	kg−1⋅m−2⋅s3⋅A2
weber	Wb	magnetic flux	J/A  T⋅m2	kg⋅m2⋅s−2⋅A−1
tesla	T	magnetic field strength, magnetic flux density	V⋅s/m2  Wb/m2  N/(A⋅m)	kg⋅s−2⋅A−1
henry	H	electrical inductance	V⋅s/A  Ω⋅s  Wb/A	kg⋅m2⋅s−2⋅A−2
degree Celsius	°C	temperature relative to 273.15 K	K	K
lumen	lm	luminous flux	cd⋅sr	cd
lux	lx	illuminance	lm/m2	m−2⋅cd
becquerel	Bq	radioactivity (decays per unit time)	1/s	s−1
gray	Gy	absorbed dose (of ionizing radiation)	J/kg	m2⋅s−2
sievert	Sv	equivalent dose (of ionizing radiation)	J/kg	m2⋅s−2
katal	kat	catalytic activity	mol/s	s−1⋅mol

Source –  https://en.wikipedia.org/wiki/Quantity_of_electricity

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