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
Mass
1 kg = 1,000 g
1 slug = 14.59 kg
1 u (atomic mass unit) = 1.6605 x 10–27kg
Force
1 lb (pound) = 4.448 N
1 N = 105dynes
1 N = 0.2248 lb
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
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)
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
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
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
