Advertisements
Advertisements
प्रश्न
Explain this statement clearly:
“To call a dimensional quantity ‘large’ or ‘small’ is meaningless without specifying a standard for comparison”. In view of this, reframe the following statements wherever necessary:
- Atoms are very small objects
- A jet plane moves with great speed
- The mass of Jupiter is very large
- The air inside this room contains a large number of molecules
- A proton is much more massive than an electron
- The speed of sound is much smaller than the speed of light.
उत्तर
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.
- An atom is a very small object in comparison to a soccer ball.
- A jet plane moves at a speed greater than that of a super fast train.
- The mass of Jupiter is very large compared to that of the earth.
- The air inside this room contains a large number of molecules as compared to that present in a geometry box.
- A proton is much more massive than an electron
- The speed of sound is much smaller than the speed of light.
APPEARS IN
संबंधित प्रश्न
The surface area of a solid cylinder of radius 2.0 cm and height 10.0 cm is equal to ______ (mm)2.
A vehicle moving with a speed of 18 km h–1covers ______ m in 1 s.
A famous relation in physics relates ‘moving mass’ m to the ‘rest mass’ m0 of a particle in terms of its speed v and the speed of light, c. (This relation first arose as a consequence of special relativity due to Albert Einstein). A boy recalls the relation almost correctly but forgets where to put the constant c. He writes:
`m = m_0/(1-v^2)^(1/2)`
Guess where to put the missing c.
Fill in the blank by suitable conversion of unit:
3.0 m s–2= ______ km h–2
In which of the following systems can scientific data be exchanged between different parts of the world?
During a total solar eclipse the moon almost entirely covers the sphere of the sun. Write the relation between the distances and sizes of the sun and moon.
If the unit of force is 100 N, unit of length is 10 m and unit of time is 100 s, what is the unit of mass in this system of units?
Give an example of a constant which has no unit.
Calculate the solid angle subtended by the periphery of an area of 1 cm2 at a point situated symmetrically at a distance of 5 cm from the area.
A new system of units is proposed in which unit of mass is α kg, unit of length β m and unit of time γ s. How much will 5 J measure in this new system?