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Physical World And Measurement

Hello, readers 😊! Here in this unit ‘Physical World And Measurement’ you can learn about basic concepts of Physics and its Impact on our Society Fundamental Forces in Nature, Four basic Conservation Law, Physical Quantities, Measurement, System of Units, Significant Figures, Errors in Measurement.

What is Science?

The term “science” originates from the Latin word “scientia,” which means “knowledge” or “knowing.” The term “science” in Sanskrit is “विज्ञान” (vijñāna)

Science is a systematic and evidence-based approach to understanding the natural world. Through observation, experimentation, and analysis, scientists strive to uncover fundamental principles and mechanisms governing the universe. Science has revolutionized society by providing technological advancements, medical breakthroughs, and a deeper understanding of our environment. It encourages critical thinking, fosters curiosity, and promotes innovation.

For the ease of study science is divided in two branches,

1. Physical Science
   • PHYSICS
   • CHEMISTRY
2. Life Science/Biology

Physics is a fundamental branch of science that explores the fundamental principles governing the behavior of matter and energy in the universe. It delves into the nature of space, time, forces, motion, and the structure of matter. Physics encompasses a wide range of topics, including mechanics, thermodynamics, electromagnetism, optics, quantum mechanics, and relativity. Through experimental observations and mathematical models, physicists strive to understand the intricacies of the physical world and uncover the underlying laws that govern it. Physics has revolutionized technology, enabling advancements in areas such as electronics, telecommunications, energy, and transportation, and it continues to expand our understanding of the universe and drive further innovations.

Chemistry is the branch of science that deals with the composition, structure, properties, and transformations of matter. It explores the interactions between atoms and molecules, and how they form compounds and undergo reactions. Chemistry plays a vital role in numerous areas, such as medicine, agriculture, materials science, environmental studies, and energy production. It helps us understand the properties and behaviour of substances, enabling the development of new materials, medicines, and technologies. From the microscopic world of atoms to the macroscopic world of chemical reactions, chemistry provides insights into the building blocks of our universe and offers practical applications that impact our daily lives.

Life Science, also known as Biology, is a field of study dedicated to understanding the complexity of living organisms. It explores the diverse forms of life, from microscopic cells to intricate ecosystems. Biology encompasses various sub-disciplines such as botany, zoology, genetics, and microbiology. Through observation, experimentation, and analysis, biologists investigate the structure, function, growth, and interactions of living organisms. They explore topics like evolution, genetics, physiology, ecology, and molecular biology. Life Science plays a vital role in fields like medicine, agriculture, environmental conservation, and biotechnology. It provides insights into the intricate mechanisms of life, enabling us to better understand ourselves and the natural world around us.

INDEX

QUIZ from unit Physical World And Measurement

Hello, readers 😊! Here is a quiz for class 11th PHYSICS on the topics Measurement of physical quantities, Dimensional Analysis and Significant figures. Take the quiz and evaluate yourself.

Measurement QUIZ / MCQs

1

Created on August 19, 2022 By pankaj

Class 11 UNIT 01 Topic: Measurement

1 / 9

1) Light year is the unit of

 

a) Time

b) Distance

c) Velocity

d) Intensity of light

2 / 9

2)

a) 2.25mm

b) 2.20mm

c) 1.20mm

d) 1.25mm

3 / 9

3) Light year is used to measure

 

a) distance between stars

b) distance between atoms

c) Time between two Eras  

d) stationery charge

4 / 9

4) Three students Arjun, Ravi and Abhishek are asked to find the mass of a piece of metal whose mass is known to be 0.520 gram. They obtained following data.

Which of the following statement is correct regarding observations recorded by students.

a) Observations recorded by Arjun is neither very precise nor accurate.

b) Observations recorded by Ravi is more precise but not accurate

c) Observations recorded by Abhishek is more precise and accurate

d) None of them is correct

5 / 9

5) A student measured the length of a rod and wrote it as 3.5 0 cm. Which instrument did he use to measure it ?

 

a) A metre scale

b) A vernier calipers where the 10 divisions in vernier scale match with 9 divisions in main scale and main scale has 10 divisions in 1 cm.

c) A screw gauge having 50 divisions in the circular scale and pitch as 1 millimeter.

d) A screw gauge having 100 divisions in the circular scale and pitch as one millimeter.

6 / 9

6) A Vernier calipers has 1 mm marks on the main scale. It has 20 equal divisions on the Vernier scale which match with 16 men scale divisions. For this Vernier calipers, the list count is

a) 0.05 millimetre

b) 0.1 mm

c) 0.02 millimetre

d) 0.2 mm

7 / 9

7) Length cannot be measured by

a) fermi

b) Debye

c) micron

d) light year

Debye is the unit of electric dipole moment not of length.

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8) The diameter of a steel ball is measured using a vernier calipers which has divisions of 0.1 cm on its main scale (MS) and 10 divisions of its vernier scale (VS) match 9 divisions on the main scale (MS). Three such measurements for a ball are given as follow: if the zero error is - 0.03 cm, then mean corrected diameter is

 

a) 0.53 cm

b) 0.56 cm

c) 0.59 cm

d) 0.52 cm

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9) The difference in the length of a mean solar day and a sidereal day is about

 

 

a)  1 minute

b) 4 minute

c) 15 minute

d) 56 minute

Sidereal day is about 3 minutes 56 second sorted than a mean solar day (24 hours).

Your score is

The average score is 88%

Hello, readers 😊! Here is a quiz on the topic Measurement. Take the quiz and evaluate yourself. For more quizzes, go to www.mywebpathshala.com

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Dimensional Analysis QUIZ / MCQs

5

Created on February 18, 2022 By anirup

UNIT 01 topic: Dimensional Analysis

Hello, readers 😊! Here is quiz on topic Dimensional Analysis. Participate in quiz and evaluate yourself. For more quizzes be with www.mywebpathshala.com

1 / 12

1. (1) In which of the following pairs, the two physical quantities do not have the same dimensional formula

a) Work and Energy

b) Pressure and Stress

c) Moment of Inertia and Angular Momentum

d) Impulse and Momentum

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2. The damping force of an oscillator is directly proportional to the velocity. The units of the constant of proportionality are

a) kg m/s

b) kg/s

c) kg m/s²

d) kg s

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3. The dimensional formula of universal gravitational constant is

a) [M-¹L³T-²]

b) [M-²L³T-²]

c) [M-¹L³T-¹]

d) [M-¹L²T-²]

4 / 12

4. Which of the following 5 physical parameters have the same dimensions?
1. Energy density
2. Refractive index
3. Dielectric constant
4. Young's modulus
5. Magnetic field

a) 1 and 5

b) 3 and 5

c) 2 and 4

d) 1 and 4

5 / 12

5. Which of the following is a Dimensional constant?

a) Poisson ratio

b) Universal gravitational constant

c) Refractive index

d) Specific gravity

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6. The time dependence of physical quantity 'p' is given by p =p_o exp(-αt²), where α is a constant and t is the time. The constant α is

a) has dimensions [T²]

b) has dimensions [T-²]

c) dimensionless

d) has dimensions p

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7. Which one of the following pairs of quantities has the same dimension ?

a) Momentum and impulse

b) Force and work done

c) Pressure and force

d) Surface tension and stress

8 / 12

8. The units of Planck's constant are

a) J s

b) J/s

c) J/s²

d) J/s²

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9. If x = at + bt² , where 'x' is the distance travelled by the body in kilometres while 't' is the time in seconds, then the unit of 'b' is

a) km s²

b) km s

c) km/s²

d) km/s

10 / 12

10. The force F is given by expression F = A cos(Bx) + C sin(Dt), where x is the displacement and t is the time. Then dimensions of D/B are same as those of

a) Angular momentum

b) Velocity gradient

c) Angular velocity

d) velocity

11 / 12

11. If force (F), velocity (V) and time (T) are taken as fundamental units, then the dimensions of mass are

 

a) [FVT-¹]

b) [FV-¹T]

c) [FVT- ²]  

d) [FV-¹T-¹]

12 / 12

12. (2) Dimensions of young’s modulus and shear modulus are

a) same, and are that of force

b) different

c) same, and are that of pressure

d) same, and are that of work

Your score is

The average score is 48%

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Significant figures QUIZ / MCQs

2

Created on August 18, 2022 By pankaj

UNIT 01 Topic: Significant figures

Hello, readers 😊! Here is a quiz on the topic Significant figures. Take the quiz and evaluate yourself. For more quizzes, go to www.mywebpathshala.com

1 / 4

1) In which of the following result  is/are correctly represented to an appropriate number of significant figures?
1) 7.21+12.141+0.0028 = 19.354
2) 75.5×125.2×0.51=4800

 

a) (1) is correct because in addition or substraction, final result should have same number of significant figures as that of the original number with maximum number of significant figures.

b) (2) is correct because in multiplication or division, final result should have same number of significant figures as that of the original number with minimum number of significant figures.

c) Both are correct

d) None of these is correct

2 / 4

2) The respective number of significant figures for the numbers 23.023, 0.0003 and 2.1×10-³ are

a) 4, 4, 2

b) 5, 1, 2

c) 5, 1, 5

d) 5, 5, 2

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3) The significant figures of the number 6.0023 are

a) 1

b) 5

c) 4

d) 3

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4) Which of the following is false regarding rules of significant figures

a) All zero to the right of a decimal point are insignificant

b) All zero to the right of a decimal point but to the left of a nonzero digit are not significant

c) The number of significant figures doesn't depend on the system of units

d) 34500 have five significant figures

Your score is

The average score is 63%

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