Measurements, Units, Physics Quantities, Dimensional Formula, Principle of Homogeneity.
Physics measurements are the bedrock of scientific analysis, enabling accurate characterization of physical quantities. These are measured in standardized quantities, like meters for length, kilograms for mass, and seconds for time. Selections are made using scientific instruments and techniques to ensure accuracy and precision, i.e., they are comparable and reproducible scientific observations.
Fundamental and Derived Quantities
There are two types of physical quantities i.e. fundamental and derived quantities. Fundamental quantities, like length, mass, time, electric current, and temperature, establish the basic principles of all measurement systems. Derived quantities, such as velocity, force, and energy, can be defined in terms of base quantities through mathematical relationships. These characteristics must be known for solving problems correctly in physics.
Dimensional Analysis and Principle of Homogeneity
Based on the idea that dimensions must be consistent in all terms throughout a physical equation, you can use dimensional analysis to check whether or not a physical equation is correct. With this technique, you represent physical quantities with respect to a dimensional formula that expresses them as combinations of fundamental dimensions (M for mass, L for length, T for time). The Principle of Homogeneity states that whenever you have a valid equation, all terms in a valid equation must have identical dimensions, ensuring logical consistency.
Units of Measurement
It sets a standard for measuring all of the physical quantities and is called System of Units (SI). Examples of SI units include the meter (m) for length, kilogram (kg) for mass, and second (s) for time. Using correct significant figures and scientific notation magnifies precision in measurement and makes it easy to perform calculations and reduce errors.
Errors in Measurement
Measurement errors are unavoidable and can be classified as systematic errors, random errors, and gross errors. Systematics are due to things like bad instruments or calibration issues, and randomness is due to unknown variables. Gross errors occur due to human mistakes in reading instruments or recording data. Minimizing these errors improves the accuracy of experimental results.
Entry Test Physics Measurements MCQS Online Preparation Sample Paper 1 Questions with Answer
1. The Physical sciences deals with:
- Both
- None of these
- Non-living things correct
- Living things
2. What type of science is physics?
- Living things
- Experimental science correct
- Non-living things
- None of these
3. Base quantities are those which?
- Further, divide
- Can be derived
- None of these
- Remain the same correct
4. Physics is an important and basic part of physical sciences which is a:
- Mathematical science
- Statistical Science
- Experimental science correct
- None of these
5. The diameter of a nucleus is:
- 10¯¹⁶ correct
- 10¯¹⁵
- 10¯¹²
- None of these
6. The distance from Earth to the Sun is?
- 10⁸m
- 10⁹m
- 10¹⁰m correct
- 10¹¹m
7. Astrophysics is the branch of physics that deals with the
- Physics of Earth’s crust
- The physics of stars and galaxies correct
- None of these
- Physics of oceans
8. Aerodynamics is a branch of physics that deals with the?
- Thermodynamics
- Hydrodynamics
- Dynamics
- None of these correct
9. High energy physics is the physics of?
- Astrophysics
- Subatomic particles correct
- Plasma Physics
- Extra nucleus
10. Types of physical quantities are:
- 1
- 3
- 2 correct
- None of these
11. Derived quantities are those which can
- Be subdivided
- Not derived
- None of these
- Be derived from other quantities correct
12. Physics deals with the study of:
- Matter and Energy and their relationship correct
- Outer atmosphere
- Matter and Energy
- None of these
13. Solid-state physics is the branch of physics that deals with the
- Atoms and molecules
- b and c correct
- Structure
- Properties
14. The biological sciences deal with the?
- Living things correct
- None of these
- Non-living things
- Both
15. The diameter of an atom is?
- 10¯¹²m
- 10¯¹⁴m
- 10¯⁷m
- 10¯¹⁰m correct
16. How many main frontiers are of fundamental science?
- 1
- None of these
- 2
- 3 correct
17. The relativistic mechanics in which objects move?
- Greater than c
- Approach to C correct
- Equal to c
- Less than c
18. The study of nature has been classified into branches:
- 2 correct
- 3
- 4
- None of these
19. Plasma physics is the branch of physics that deals with the?
- Atoms and molecules
- Molecules neutrals
- Ions correct
- All of these
20. The diameter of the Milky Way is?
- 10¹⁸m
- 10¹⁵m
- 10¹⁷m
- 10²⁰m correct
Physics Measurements MCQS Online Preparation Sample Paper 2 Questions with Answer
1. The period of typical radio waves is
- 1 x 10¯⁶ se c correct
- 1 x 10¯⁸ sec
- 1 x 10¯⁵ sec
- 1 x 10¯⁹ sec
2. The number 0.0023 should be expressed as
- 2.3 x 10¯³ correct
- None of these
- 0.23 x 10¯⁴
- 0.023 x 10¯²
3. The age of the Earth is
- 1.4 x 10¹⁷ sec correct
- 1.4 x 10¹⁹ sec
- 1.4 x 10¹⁵ sec
- 14 x 10¹⁷ sec
4. Steradian is a unit of
- radius
- None of these
- solid angle correct
- plane angle
5. The error of any measurement may occur due to?
- Faulty apparatus
- Inappropriate method
- Negligence
- All of these correct
6. The period of audible sound waves is
- 1 x 10¯² sec
- 1 x 10¯¹ sec
- 1 x 10¯³ sec correct
- 1 x 10¯⁴ sec
7. The distance to the milkway is
- 10²⁰m
- 10³⁰m correct
- 10³¹m
- 10²⁹m
8. Time between the normal heartbeats is
- 8 x 10¯² sec
- 8 x 10¯¹ sec correct
- None of these
- 8 x 10¯³ sec
9. The uncertainty of any measurement may occur due to?
- All of these correct
- Limitation to an instr5ument
- Natural imperfections of a person’s sense
- Natural vibrations of the object
10. Radian is an angle which is?
- Angle
- Plane angle correct
- Solid angle
- None of these
11. One year is equal to ___________ Seconds.
- 3.2 x 10⁶ sec
- 3.12 x 10⁷ sec correct
- 4.3 x 10¹⁰ sec
- 4.4 x 10⁸ sec
12. The period of visible light waves is
- 2 x 10¯¹¹ sec
- 2 x 10¯¹⁵ se c correct
- 2 x 10¯¹⁰ sec
- 2 x 10¯¹⁴ sec
13. The number 134.7 should be written as
- None of these
- 13.47 x 10³
- 1.347 x 10² correct
- 13.47 x 10²
14. Age of the Universe is
- 5 x 10¹⁷ sec correct
- 5 x 10¹⁹ sec
- 5 x 10¹⁵ sec
- None of these
15. One day is equal to
- 9.3 x 10³ sec
- None of these
- 8.6 x 10⁴ sec correct
- 5 x 10⁷ sec
16. Period of vibration of an atom in a solid is?
- 1 x 10¯¹⁹ sec
- 1 x 10¯¹⁶ sec
- 1 x 10¯¹³ sec correct
- 1 x 10¯¹⁰ sec
17. The expression of scientific notation is?
- None of these
- One non-zero digit left of decimal correct
- Two zeros and one non-zero digit left of the decimal
- One zero digit left of the decimal
18. In the measurement 12.7 measures?
- Two accurately known digit
- Two accurately known digits and one doubtful correct
- One accurately known digit
- None of these
19. Steradian is the
- Three-dimensional angle correct
- One dimensional angle
- None of these
- Two-dimensional angle
20. Scientific notation which can be expressed in the
- None of these
- Negative powers
- Powers of ten correct
- Decimals
Entry Test Physics Measurements MCQS Online Preparation Sample Paper 3 Questions with Answer
1. The time taken by the light to travel from Pluto to Earth is?
- 6 hrs 20 sec
- 5 hrs 20 sec correct
- 76 hrs 20 sec
- 4 hrs 20 sec
2. The precision of measurement in Physics depends
- Average values and Error-free instrument
- Error-free instrument and Least count of instrument correct
- Least count of instruments and Average values
3. In integers such as 8,000 Kg, significant zeros are determined by the instrument when the least count is 1 Kg.
- 8.000 x 10³ Kg correct
- 8.0000 x 10³ Kg
- 8.00 x 10³ Kg
- 8.0 x 10³ Kg
4. According to equation E = mc² 1 Kg mass is actually the energy equal to
- 8 x 10¹⁵ J
- 8 x 10¹⁸ J
- 9 x 10¹⁷ J
- 9 x 10¹⁶ J correct
5. The mass of a Uranium atom is?
- 10¯²⁵ KG correct
- 10¯¹⁵ Kg
- 10¯²⁰ Kg
- 10¯¹⁰ Kg
6. For assessment of total uncertainty when percentage uncertainties are?
- Subtracted
- Added correct
- Multiplied
- Divided
7. For assessment of total uncertainty when added or subtracted the absolute uncertainties are?
- Multiplied
- Divided
- Subtracted
- Added correct
8. Random error occurs when repeated measurements of the quantity under the same conditions give?
- None of these
- Different values correct
- Equal values
- Increasing Values
9. The time taken by the light to travel from the Sun to Earth is?
- 8 min 20 sec correct
- 5 min 20 sec
- 4 min 20 sec
- 9 min 20 sec
10. by dimensional analysis, we can find?
- Correctness of formula
- All of these correct
- Physical nature
- Derivation of formula
11. The dimension stands for the nature of a physical quantity which is?
- None of these
- Numerical
- Quantity
- Quantitative correct
12. In color printing, the entire range of colors uses just?
- Five colours
- None of these
- Four colours correct
- Three colours
13. Lightly year is measured in?
- Time
- Length correct
- Speech
- None of these
14. Systematic error refers to an effect that influences a particular quantity for the measurements which are?
- None
- Some
- A and B
- All correct
15. 8.233 m, 2:105m and 1.05 cm are the length, breadth and thickness respectively, find volume of the sheet correct upto appropriate significant digits?
- 7.15 x 10¯² m³ correct
- 7.85 x10¯² m³
- 8.25 x 10¯³ m³
- None of these
16. The travel time of light from the Moon to Earth is?
- 1 min
- 3 min 30 sec
- 1 min 20 sec correct
- 2 min 10 sec
17. Total mass when silver coins are added to box as 2.2 Kg, 0.01001 Kg and 0.01002 Kg correct to appropriate precision?
- 2.3 Kg
- 2.43 Kg
- 2.67 Kg
- 2.2 Kg correct
18. In the assessment of total uncertainties when a power factor is involved, the percentage uncertainty is?
- Added
- Divided by that power
- None of these
- Multiplied by that power correct
19. We are living in the age of?
- Technology
- Information technology correct
- None of these
- Space age
20. Accuracy of a measurement depends on?
- Fractional uncertainty correct
- None of these
- Less absolutely
- Percentage uncertainty
Conclusion
Understanding physics measurements is crucial for solving ECAT entry test problems effectively. Mastering concepts such as dimensional analysis, units, significant figures, and measurement errors will significantly improve accuracy and confidence in answering test questions. For more practice MCQs and sample papers, visit Nokryan.com.