Home
Class 11
PHYSICS
Why is that for both very small as well ...

Why is that for both very small as well as very large (in addition to ordinary) quantities, the physical measurements are usually expressed in scientific notation, with powers of ten ?

Text Solution

Verified by Experts

To denote the precision of the measurement.
Promotional Banner

Similar Questions

Explore conceptually related problems

If a large quantity of dry grass is set on fire in forests then it is very difficult to put off the fire. Why?

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: (a) atoms are very small objects (b) a jet plane moves with great speed (c) the mass of jupiter is very large (d) the air inside this room contains a large number of molecules (e) a proton is much more massive than an electron (f) the speed of sound is much smaller than the speed of light.

Covalent molecules formed by heteroatoms bound to have some ionic character. The ionic character is due to shifting of the electron pair towards A or B in the molecule AB. Hence, atoms acquire small and equal charge but opposite in sign. Such a bond which has some ionic character is described as polar covalent bond. Polar covalent molecules can exhibit dipole moment. Dipole moment is equal to the product of charge separation, q and the bond length, d for the bond. The unit of dipole moment is Debye. One Debye is equal to 10^(-18) esu cm. Dipole moment is a vector quantity. It has both magnitude and direction. Hence, dipole moment of molecules depends upon the relative orientation of the bond dipoles, but not on the polarity of bonds alone. A symmetrical structure shows zero dipole moment. Thus, dipole moments help to predict the geometry of the molecules. Dipole moment values can be used to distinguish between cis-and traps-isomers, ortho-, meta-and para-forms of a substance, etc. The percentage of ionic character of a bond can be calculated by the application of the following formula : % " ionic character " = ("Experimental value of dipole moment ")/("Theoretical value of dipole moment ") xx 100 The dipole moment of NF_(3) is very much less than that of NH_(3) because :

(a) A comb run through one’s dry hair attracts small bits of paper. Why? What happens if the hair is wet or if it is a rainy day? (Remember, a paper does not conduct electricity.) (b) Ordinary rubber is an insulator. But special rubber tyres of aircraft are made slightly conducting. Why is this necessary? (c) Vehicles carrying inflammable materials usually have metallic ropes touching the ground during motion. Why? (d) A bird perches on a bare high power line, and nothing happens to the bird. A man standing on the ground touches the same line and gets a fatal shock. Why?

Answer the following questions: (a) A steady current flows in a metallic conductor of non-uniform cross-section. Which of these quantities is constant along the conductor: current, current density electric field, drift speed ? (b) Is Ohm's law universally applicable for all cnducting elements ? If not, give examples of elements which do not obey Ohm's law. (c ) A low voltage suply from which one needs high currents must have very low internal resistance.Why (d) A high tension (HT) supply of say, 6kV must have a very large internal resistance, Why ?

The electron drift speed in metals is small (~ ms^(-1)) and the charge of the electron is also very small (~ 10^(-19)C) , but we can still obtain a large amount of current in a metal. Why?