An 11th physics guide typically covers the fundamental concepts and principles of physics, preparing students for advanced studies and exams. Here's an overview of the key topics and concepts usually included:
*Units and Dimensions*
1. Units (SI, CGS, FPS)
2. Dimensional analysis
3. Convers...
,11 PHYSICS UNIT - 1 NATURE OF PHYSICAL WORLD AND MEASUREMENT COMPLETE GUIDE AND MODEL QUESTION PAPER
5. Which of the following has the highest number of significant figures?
PART - I MULTIPLE CHOICE QUESTIONS & ANSWERS WITH SOLUTIONS (a) 0.007 m2 (b) 2.64x1024 kg
1. One of the combinations from the fundamental physical constants is hc/ G . (c) 0.0006032 m2 (d) 6.3200 J
The unit of this expression is Soultion :
(a) kg2 (b) m 3 • All zeros to the right of a decimal point and to the right of a non-zero digit are
(c) s -1 (d) m significant. Hence
Soultion : (a) Significant figure of 0.007 is = 1
ℎ𝐶 (𝐽 𝑠)(𝑚 𝑠−1 ) (𝑁 𝑚 𝑠)(𝑚 𝑠−1 ) (b) Significant figure of 2.64x1024 is = 3
• Unit of = = = 𝑘𝑔2 (c) Significant figure of 0.0006032 is = 4
𝐺 𝑁 𝑚2 𝑘𝑔−2 𝑁 𝑚2 𝑘𝑔−2
𝟐 (d) Significant figure of 6.3200 is = 5
Answer (a) 𝒌𝒈 Answer (d) 6.3200 J
2. If the error in the measurement of radius is 2%, then the error in the 6. If π = 3.14, then the value of π2 is
determination of volume of the sphere will be (a) 9.8596 (b) 9.860
(a) 8% (b) 2% (c) 9.86 (d) 9.9
(c) 4% (d) 6% Soultion :
Soultion :
4 • 𝜋 2 = 3.14 𝑋 3.14 = 9.8596
• Volume of the sphere ; 𝑉 =
3
𝜋 𝑟3 • As the input data (3.14) has 3 significant figure, the answer should be restricted
• So error in the measurement ; to 3 significant figure by rounding off as ; 𝜋 2 = 9.86
∆𝑉 ∆𝑟
= 3 ( 𝑟 ) = 3 (2%) = 6% Answer (c) 9.86
𝑉 7. Which of the following pairs of physical quantities have same dimension?
Answer (d) 𝟔% (a) force and power (b) torque and energy
3. If the length and time period of an oscillating pendulum have errors of 1% and (c) torque and power (d) force and torque
3% respectively then the error in measurement of acceleration due to gravity Soultion :
is • Dimensional formula for,
(a) 4% (b) 5% (a) Force (𝐹 = 𝑚𝑎) ⟹ [𝑀𝐿𝑇 −2 ] ;
𝑊
Power(𝑃 = ) ⟹ [𝑀𝐿2 𝑇 −3 ]
(c) 6% (d) 7% 𝑡
Soultion : (b)Torque (𝜏 = 𝐹 𝑟) ⟹ [𝑀𝐿2 𝑇 −2 ] ; Energy(𝐸 = 𝑊) ⟹ [𝑀𝐿2 𝑇 −2 ]
𝑊
(c) Torque (𝜏 = 𝐹 𝑟) ⟹ [𝑀𝐿2 𝑇 −2 ] ; Power(𝑃 = ) ⟹ [𝑀𝐿2 𝑇 −3 ]
𝑙 𝑙 𝑡
• Time period is given by ; 𝑇 = 2 𝜋√
𝑔
(or) 𝑇2 = 4 𝜋2 𝑔 (d) Force (𝐹 = 𝑚𝑎) ⟹ [𝑀𝐿𝑇 −2 ] ; Torque (𝜏 = 𝐹 𝑟) ⟹ [𝑀𝐿2 𝑇 −2 ]
𝑙 Answer (b) torque and energy
• Hence acceleration due to gravity ; 𝑔 = 4 𝜋2 𝑇2 8. The dimensional formula of Planck's constant h is
• So error in the measurement ; (a) [ML2T-1] (b) [ML2T-3]
∆𝑔 ∆𝑙 ∆𝑇
= +2 = 1% + 2(3%) = 7% (c) [MLT ] -1 (d) [ML3T-3]
𝑔 𝑙 𝑇
Soultion :
Answer (d) 𝟕% • Energy of photon ; 𝐸 = ℎ 𝜈 (here ℎ →Plank’s constant)
4. The length of a body is measured as 3.51 m, if the accuracy is 0.01m, then the 𝐸
2
[𝑀 𝐿 𝑇
−2
]
percentage error in the measurement is • Hence dimension of ℎ =
𝜈
= −1 = [𝑀 𝐿2 𝑇−1 ]
[𝑇 ]
(a) 351% (b) 1%
(c) 0.28% (d) 0.035% Answer (a) [𝑴 𝑳𝟐 𝑻−𝟏 ]
Soultion : 9. The velocity of a particle v at an instant t is given by v = at + bt2. The
• Error in the measurement; dimensions of b is
∆𝑙 0.01 (a) [L] (b) [LT-1]
𝑙
𝑋100% = 3.51 𝑋100% = 0.0028 𝑋 100% = 0.28% (c) [LT-2] (d) [LT-3]
Answer (c) 𝟎. 𝟐𝟖 %
, 11 PHYSICS UNIT - 1 NATURE OF PHYSICAL WORLD AND MEASUREMENT COMPLETE GUIDE AND MODEL QUESTION PAPER
6. Define physical quantity.
PART - II & III 2 & 3 MARK SHORT ANSWER QUESTIONS & ANSWERS • Quantities that can be measured, and in terms of which, laws of physics are
described are called physical quantities.
1. What is mean by science?
Examples - length, mass, time, force, energy, etc
• The word ‘science’ has its root in the Latin verb scientia. meaning “to know”
• Physical quantities are classified into two types. They are fundamental and
• In Tamil language, it is “அறிவியல்” meaning ‘knowing the truth’
derived quantities.
• Science is the systematic organization of knowledge gained through observation, 7. Briefly explain the types of the physical quantities .
experimentation and logical reasoning.
Fundamental quantity Derived quantity
• The knowledge of science dealing with non -living things is physical science
Quantities which cannot be Quantities that can be expressed
(physics and chemistry) and that dealing with living things is biological science
expressed in terms of any other in terms of fundamental quantities
(zoology and botany)
physical quantities are called are called derived quantities.
2. What is called scientific method and what are the features involved in this
Fundamental or base quantities
method?
Examples - Examples -
• The scientific method is a step-by-step approach in studying natural phenomena
Length, mass, time, electric current, Area, volume, velocity,
and establishing laws which govern these phenomena . temperature, luminous intensity and acceleration, force, etc.
• Any scientific method involves the following general features. amount of substance
(i) Systematic observation 8. Define units. What are its types?
(ii) Controlled experimentation • An arbitrarily chosen standard of measurement of a quantity, which is
(iii) Qualitative and quantitative reasoning accepted internationally is called unit of the quantity.
• Basically there are two types of units. They are fundamental units and
(iv) Mathematical modeling
derived units.
(v) Prediction and verification or falsification of theories 9. Distinguish between fundamental units and derived units
3. What do you mean by physics?
fundamental units derived units
• The name Physics was introduced by Aristotle in the year 350 BC The units in which the fundamental The units in which all the physical
• The word ‘Physics’ is derived from the Greek word “Fusis”, meaning nature. quantities are measured are called quantities which can be obtained by
• The study of nature and natural phenomena is dealt within physics. Hence fundamental or base units a suitable multiplication or division
physics is considered as the most basic of all sciences. of power on fundamental units are
• Unification and Reductionism are the two approaches in studying physics. called derived units
4. Briefly explain the role of physics in technology and society. Examples- Examples-
• Technology is the application of the principles of physics for practical purposes. m, s, kg, A, mol m/s, kg/m3,
• Physics and technology can both together impact our society directly or 10. Define f.p.s system of units.
indirectly. For example, • It is the British Engineering system of units, which uses foot, pound and second
(i) Basic laws of electricity and magnetism led to the discovery of wireless as the basic units for measuring length, mass and time respectively
communication technology which has shrunk the world with effective 11. Define c.g.s system of units.
communication over large distances. • It is the Gaussian system of units, which uses centimeter, gram and second as
(ii) The launching of satellite into space has revolutionized the concept of the basic units for measuring length, mass and time respectively
communication. 12. Define m.k.s system of units.
(iii) Microelectronics, lasers, computers, superconductivity and nuclear energy • It is the Metric system of units, which uses metre, kilogram and second as the
basic units for measuring length, mass and time respectively
have comprehensively changed the thinking and living style of human
13. Write a note on SI system?
beings.
• The SI unit system (Système International) with a standard scheme of symbols,
5. Whtat is called measurement?
units and abbreviations were developed and recommended by the General
• The comparison of any physical quantity with its standard unit is known as
Conference on Weights and Measures in 1971 for international usage in
measurement. Measurement is the basis of all scientific studies and
experimentation. scientific, technical, industrial and commercial work .
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