Accuracy in Measurements
When measuring physical quantities, accuracy is important. Accuracy represents how close a measurement comes to a true value. Accuracy in measurement is center in engineering, physics and all branches of science. It is also important in our daily life. You might have seen in jewellery shops how accurately they measure gold. What will happen if little more salt is added to food while cooking? So, it is important to be accurate when taking measurements.
Faulty instruments and human error can lead to inaccurate values. In order to get accurate values of measurement, it is always important to check the correctness of the measuring instruments. Also, repeating the measurement and getting the average value can correct the errors and give us accurate value of the measured quantity.
· Length, mass, time, temperature, electric current, intensity and mole are the fundamental units in SI system
· To find the length or thickness of smaller dimensions Vernier caliper or screw gauge are used
· Austronomical unit is the mean distance of the sun from center of the earth 1AU=1.496 × 1011m
· Light year is the distance travelled by light in one year in vacuum. 1 Light year = 9.46 × 1015m
· Parsec is the unit distance used to measure astronomical objects outside the solar system
· 1 Angstrom (Å) = 10−10 m
· SI Unit of volume is cubic metre or m3. Generally volume is represented in litre (l). 1ml=1cm3
· C/100 = (F ‒32)/180 = (K ‒273)/100 Least count of screw gauge is 0.01
· Lease count of Vernier caliper is 0.01 cm
· Common balance can measure mass accurately upto 5 g
· Accuracy of physical balance is 10 mg