The diameter of the thread is so small that it cannot be measured using a metre scale.
Wind a number of turns of threads on the metre scale so that the turns are closely touching one another.
Measure the length (l) of the windings on the scale which contains n number of turns.
A device with minimum count is the most suitable to measure length.
a)
b)
Hence, it can be inferred that an optical instrument is the most suitable device to measure length.
Magnification of the microscope = 100
Average width of hair in the field of view of the microscope = 3.5 mm
Therefore, actual thinckness of the hair =
The given statement is true because a dimensionless quantity may be large or small in comparison to some standard reference. For example, the coefficient of friction is dimensionless. The coefficient of sliding friction is greater than the coefficient of rolling friction, but less than static friction.
a) An atom is a very small object in comparison to a soccer ball.
b) A jet plane moves with a speed greater than that of a bicycle.
c) Mass of Jupiter is very large as compared to the mass of a cricket ball.
d) The air inside this room contains a large number of molecules as compared to that present in a geometry box.
e) A proton is more massive than an electron.
f) Speed of sound is less than the speed of light.