Dimensional Analysis and its Applications

Author:NCERT
11th CBSE
IMPORTANT

Important Questions on Dimensional Analysis and its Applications

HARD
IMPORTANT

An artificial satellite is revolving around a planet of mass M and radius R, in a circular orbit of radius r. From Kepler’s Third law about the period of a satellite around a common central body, square of the period of revolution T is proportional to the cube of the radius of the orbit r. Show using dimensional analysis, that
  T= kRr3g
where k is a dimensionless constant and g is acceleration due to gravity.
 

HARD
IMPORTANT

If velocity of light c , Planck’s constant h and gravitational constant G are taken as fundamental quantities then express mass, length and time in terms of dimensions of these quantities.

MEDIUM
IMPORTANT

Mars has approximately half of earth's diameter. When it is closest to earth, it is at about 12 A.U. from the earth. Calculate what size it will appear when seen through the same telescope. (Comment: This is to illustrate why a telescope can magnify planets but not stars.)

MEDIUM
IMPORTANT

Calculate the solid angle subtended by the periphery of an area 1cm2 at a point situated symmetrically at a distance of 5cm from the area.

MEDIUM
IMPORTANT

Calculate the length of the arc of a circle of radius 31.0 cm which subtends an angle of π6 at the center.

MEDIUM
IMPORTANT

Why length, mass and time are chosen as base quantities in mechanics?

MEDIUM
IMPORTANT

A function fθ is defined as:

f(θ)=1-θ+θ22!-θ23!+θ44!-

Why is it necessary for f(θ) to be a dimensionless quantity?

MEDIUM
IMPORTANT

Name the device used for measuring the mass of atoms and molecules.

MEDIUM
IMPORTANT

The radius of atom is of the order of 1 1 and radius of nucleus is of the order of fermi. How many magnitudes higher is the volume of atom as compared to the volume of nucleus?