 # Conversion Factors in Physics

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Last updated on September 10th, 2019 at 03:22 am

In physics, you are frequently asked to convert between units of measurement. Conversion factors are therefore very important in physics. For example, you may be asked to measure the number of kilometers your school bus travels in an hour and may need to convert the result in a mile. A handy conversion factor table between different units is therefore very useful. Here we have listed some common conversion factors you may require while solving your physics problems. The download link is available at the bottom of this post.

## Mass :

1 tonne = 1000 kg
1 kg = 1000 gm
1 kg = 2.2046 pound (lb) = 6.022 x 1026 amu
1 lb = 453.6 gm
1 atomic mass unit (amu) = 1.6606 x 10-27 kg
1 amu = 931.50 MeV/c2
1 electron mass = 9.11 x 10-31 kg = 9.11 x 10-28 g = 5.46 x 10-4 atomic mass unit (amu)
1 proton mass = 1.00728 atomic mass unit (amu)
1 neutron mass = 1.00866 atomic mass unit (amu)

An atomic mass unit is defined as 1/12 the mass of an carbon-12 atom, which has six protons and six neutrons in its nucleus.

## Length :

1 in = 2.54 cm
1 ft = 12 in = 30.48 cm
1 mile = 1.609 km
1 cm = 0.394 in
1 m = 3.28 ft = 39.37 in
1 km = 0.621 mile
1 astronomical unit (AU) = 1.50 x 108 km
1 light year (LY) = 9.461 x 1012 km
1 parsec = approximately 3.26 light year (LY)
1 A = 0.1 nm
1 nm = 10-9 m

## Time :

1 Day= 86400 Sec
1 Year = 3.16×107 Sec

## Temperature :

°F = 9/5 x °C + 32
°C = (°F – 32) x 5/9
Absolute Temperature, Kelvin, K = °C + 273.15
0 K = -273.15 °C = -459.72 °F

## Area :

1 m2 = 104 cm2 = 10.76 ft2
1 in2 = 0.00694 ft2
1 ft2 = 144 in2
1 mile2 = 2.59 km2

## Volume :

1 in3 = 0.000579 ft3 = 16.4 cm3
1 ft3 = 1728 in3 = 0.0283 m3
1 m3 = 106 cm3 = 1000 L = 35.3 ft3
1 liter (L) = 1000 cm3

## Speed :

1 m/s = 3.28 ft/s= 2.24 mile/h
1 Km/h= 0.621 mile/h = 0.278 m/s

## Force and Pressure :

1 N = 105 dyne = 0.2248 lb wt
1 lb wt = 4.4482 N
1 kg wt = 2.2046 lb wt

1 Pa = 1 N/m2= 10 dyne/cm2 = 9.869 × 10-6 atm
1 bar = 100 kPa
1 atm = 1.01325×105 Pa = 76 cm-Hg
1 atm = 29.9 in-Hg
1 atm = 33.8 ft Water
1 torr = 1 mm Hg = 133.32 Pa
1 atmosphere (atm) = 1.01325 × 106 dynes/cm2 = 14.70 lbwt/in2

## Energy and Power :

1 Joule =107 erg=0.239 Cal
1 KW-h= 3.6×106 Joule
1 cal= 4.186 J = 3.968 × 10-3 Btu
1 eV = 1.602×10-19 J
1 Btu (British thermal unit) = 778 ft lb-wt = 1055 joules = 0.293 watt-hr
1 kilowatt hour (kw hr) = 3.60 × 106 joule = 860 kcal = 3413 Btu
1 electron volt (ev) = 1.602 × 10-19 joule

1 Horse Power (hp)= 745.7 Watt = 550 ft lb wt/sec
1 Watt = 1 Joule/Sec = 107 erg/sec = 0.2389 Cal/sec
1 watt = 1.341 x 10-3  hp
1 Horse Power (hp) = 550 ft lbwt/sec = 33,000 ft lb-wt /min = 745.7 Watt
1 Kilo Watt (kw) = 1.341 hp = 737.6 ft lbwt/sec = 0.9483 Btu/Sec

## Magnetism :

1 Tesla= 1 Wb/m2 = 104 gauss