# Physical Quantities and Their Measurements

## ðŸ‘‰All Chapter ContentsðŸ‘ˆÂ

Physical Quantities and Their Measurements

Measuring Instruments

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Development of Physics

Who invented the electric battery?

Alexander Volta invented an electric battery

According to Newton's concept of time and space, how is our universe built?

According to Newton's concept of time and space our universe is built in three dimensions.

What are fundamental quantities?

The quantities that are independent and neutral, and do not depend on any other quantity rather other quantities depend on them, are called fundamental quantities.

What is fundamental unit?

A fundamental unit is that which is independent of any other unit or which can neither be changed nor can be related to any other fundamental unit.

Physical Quantities and Their Measurement

What is dimension?

The power of fundamental quantities in a physical quantity is called its dimension.

Measuring Instrument

What is meter scale?

The scale used to measure small lengths (100 cm or 1 m) is called meter scale.

What is Vernier constant?

The difference between the smallest main scale division and the vernier scale division is called the vernier constant.

What is screw pitch?

The displacement after one unit rotation of the circular scale that is the length moved along the linear scale that length is called the screw pitch.

What is least count of a screw gauge?

If the circular scale is rotated only one division the distance that the screw covers for that one rotation is said to be least count of the screw gauge.

When one unit of the circular scale of a screw gauge is rotated, the length moved by the edge of the circular scale along its linear scale is called the least count of the screw gauge.

Error and Accuracy

What is an instrumental error?

The instrumental error refers to the error of a measuring instrument or the difference between the actual value and the value indicated by the instrument.

What is observational error?

The error caused by the operator while taking measurements is called observational error.

What is absolute error?

The difference of the measured value with respect to the actual value is called the absolute error.

## Question Bank

• What is physics?
• Describe the scope of physics.
• What is the main goal of physics?
• What are the branches of physics?
• Who is famous for solar eclipse predictions?

## 1.2 Scope of Physics

• Describe the scope of physics.
• What is classical physics?
• What is modern physics?

• Who is famous for solar eclipse predictions?
• What does the word atom mean?
• Who says the matter has an inseparable unit?
• What is the contribution of Archimedes to physics?
• What did Hygen contribute to physics?
• Who wrote the encyclopedia about the history of nature?
• Who is the proponent of the experimental scientific method?
• Who made the model of the aircraft?
• Why is Dr. Gilbert so memorable?
• Who discovered the law of refraction of light?
• What did Hygen contribute to physics?
• Who invented the air pump?
• Who measures the speed of light?
• Who presented the idea of solar-centric theory?
• What did Kepler say about the direction of the sun?
• Write Galileo's contribution to physics?
• Write Newton's contribution to physics.
• Who invented calculus?
• Why did the Industrial Revolution take place in Europe in the eighteenth century?
• Who shows that electric current has a magnetic action?
• Explain logically that the wonderful advances in physics have taken place in the twentieth century.
• The nucleus is fissionable, who said in what year?
• What happens as a result of nuclear fission?
• Who provides the theory of relativity?
• Who presented clear proof of Plank's quantum theory?
• Which scientist has been awarded the Nobel Prize for his outstanding contribution to the discovery of the weakest force in the aggregation of fundamental forces?
• Explain the discovery of physics has changed our way of life.

• Describe the objective of physics.
• Physics reveals the mysteries of nature - explain.
• Physics describes the laws of nature - explain.
• Technology improves by following the basic principles of physics - explain.

## 1.5 Physical Quantities and Their Measurements

• What do you mean by quantity?
• What are fundamental quantities?
• Write all the fundamental quantities.
• What are derived quantities?
• Write some examples of derived quantities.
• Proof that force is a derived quantity.
• Why acceleration is a derived quantity?
• Write differences between fundamental and derived quantities.
Units of Measurement
• What is the unit of measurement?
• What is an SI unit?
• Why is a unit needed to express the measure of a quantity?
• Write the definition of all fundamental quantities.
• What is meter
• What is a kilogram?
• What is an ampere?
• Write the symbol of a unit of fundamental quantities.
• 1 nanosecond is equal to how many seconds?
• How many meters is equal to 1 petameter?
• What is a scientific symbol?
• Express the number 0.0000000005687 in a scientific way.
• Express the number 265945665665 in a scientific way.
• Explian the advantages of the scientific method of numbers.
Dimensions
• What is a dimension?
• Determine the dimension of force?
• Why it is necessary to know the level equations of different quantities?
Scientific symbols and notations
• What are the methods to follow to write the symbol of units and different numbers?
• Explain the reasons for using scientific symbols and prefixes.

• What is a meter scale?
• How to measure with a meter scale?
• What is the vernier constant?
• How to determine the vernier constant of slide calipers?
• What is vernier coincidence?
• What does vernier coincidence 7 meant?
• Why is the vernier scale used with the main scale?
• Write the requirements of the vernier scale for precise and accurate measurements.
• What are slide calipers?
• How to determine the diameter of a cylinder with the help of slide calipers?
• Describe how to determine the size of a cylinder using a slide caliper.
• Describe the need for slide calipers for fine measurement.
• What is a screw gauge?
• How to measure by screw gauge?
• What is pitch?
• What is the least count?
• How to determine the least count?
• What is a stopwatch?
• How to measure time with the help of a stopwatch?
• Mathematical Problems: