Definitions [27]
Define mass.
The quantity of matter contained in a body is known as its mass.
Mass is the measure of the amount of matter in an object.
State or define the following term:
An hour
It is defined as 1/24 the part of the mean solar day.
Define Standard metre.
The standard metre is defined in terms of the speed of light, according to which one metre is the distance travelled by light in `1/(299,792,458)` of a second in the air (or vacuum).
State or define the following term:
Mean solar day
The average of the varying solar days, when the earth completes one revolution around the sun, is called mean solar day.
State or define the following term:
Minute
It is defined as the 1/1440 part of the mean solar day.
State or define the following term:
Year
One year is defined as the time in which earth completes one complete revolution around the sun.
Define measurement.
Measurement is the process of comparison of the given physical quantity with the known standard quantity of the same nature.
Define standard meter.
A standard metreis equal to 1650763.73 wavelengths in vacuum, of the radiation from krypton isotope of mass 86.
Define a fundamental quantity.
The physical quantities like mass, length and time which do not depend on each other are known as fundamental quantities.
State or define the following term:
Solar day
The time taken by the earth to complete one rotation about its own axis is called solar day.
State or define the following term:
Second
“A second is defined as 1/86400 the part of a mean solar day.”
OR
Second may also be defined “as to be equal to the duration of9,192,631,770 vibrations corresponding to the transition between two hyperfine levels of cesium – 133 atoms in the ground state.”
Define one metre, the S.I. unit of length. State it's one multiple and one submultiple.
One metre is defined as the distance travelled by light in the air in `1/(299,792,458)` of a second.
The S. I. unit of length is meter.
Multiple of metre = Kilometre (km).
Submultiple of metre = Centimetre (cm)
Define mass Mention its unit.
Mass is the amount of matter contained in a body. Its unit is a kilogram (kg).
Define the term density of a substance.
The density of a substance is defined as the mass of a unit volume of that substance.
`"Density" = "Mass"/"Volume"`
Define standard unit.
Unit is the quantity of a constant magnitude which is used to measure the magnitudes of other quantities of the same nature.
Define least count of any device.
The smallest value that can be measured by the measuring instrument is called its least count.
Define one kilogram, the S.I. unit of mass.
One kilogram (kg) is the S.I. unit of mass. It is defined as the mass of the international prototype of the kilogram, which is a platinum-iridium alloy cylinder stored at the International Bureau of Weights and Measures in France.
Define mass.
Mass is the measure of the amount of matter in an object. It is a fundamental property of matter and does not change with location or the object’s state.
Temperature is a parameter which tells the thermal state of a body (i.e., the degree of hotness or coldness of the body). It determines the direction of flow of heat when two bodies at different temperatures are placed in contact.
Define coefficient of linear expansion.
Coefficient of Linear expansion is equal to the change in length of a rod of length 1m when its temperature rises by 1°C.
Define absolute zero.
The temperature at which the pressure and volume of a gas theoretically reach zero is called absolute zero.
Define metre in terms of the wavelength of light.
One metre is defined as 1,650,763.73 times the wavelength of a specified orange-red spectral line in emission spectrum of Krypton = 86.
OR
One metre is defined as 1,553,164.1 times the wavelength of the red line in the emission spectrum of cadmium.
Define the term pitch.
“The pitch of a screw is the distance moved by the screw in one complete rotation of its head.”
OR
Pitch may also be defined as “the distance between two consecutive threads of screw measured along the axis of the screw.”
Pitch = `"Distance moved by thimble on M.S."/"Number of rotations of thimble"`
Define metre according to the old definition.
One metre is defined as the one ten-millionth part of distance from the pole to the equator.
Define the term least count as applied to a vernier callipers.
Least count of a vernier callipers is the difference between one main scale division (M.S.D.) and one vernier scale division (V.S.D.)
The weight of an object is defined as the force with which the earth attracts the object.
Mass is the amount of matter present in the object. The SI unit of mass is kg.
Key Points
- If no heat flows between two bodies in contact, they are said to be at the same temperature, even though their thermal energies may be different.
- The S.I. unit of temperature is kelvin (K), and absolute zero (0 K) is the temperature at which molecular motion ceases.
Concepts [19]
- Measurements
- Physical Quantities
- Unit and Its Types
- Unit Systems
- The International System of Units (SI)
- Measurement of Length
- Measuring Smaller Distances
- Measuring Larger Distances
- Measurement of Mass
- Measurement of Time
- The Temperature and a Thermometer
- Scales of Thermometers
- Unit Prefixes
- Rules and Conventions for Writing SI Units and Their Symbols
- Vernier Callipers
- Screw Gauge
- Devices for Measuring Mass
- Mass and Weight
- Accuracy in Measurements
