Question

2. Short answer type questions.

a) Define kilogram, the S.I. unit of mass.
b) Name and define the S.I. unit of time.
c) Name two devices used to measure the short interval of an event.​

Answer 1

Answer:

a) The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 x 10–34 when expressed in the unit J s, which is equal to kg m2 s–1, where the metre and the second are defined in terms of c and Cs.

b) A unit of time or midst unit is any particular time interval, used as a standard way of measuring or expressing duration. The base unit of time in the International System of Units (SI) and by extension most of the Western world, is the second, defined as about 9 billion oscillations of the caesium atom.

c) A chronoscope is a device used to measure short time intervals.