Physical World and Measurement

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Introduction

As we all know the word science originates from the Latin verb meaning scientia meaning “to know”. So studying science there were so many systematic attempts to understand natural phenomena in as much detail and depth as possible and use the knowledge so gained to predict, modify, and control phenomena. There were diverse physical phenomena in terms of a few concepts and laws.


Fundamental Force in Nature

Few fundamental forces in nature are:

Gravitational force

Electromagnetic force

Strong nuclear force

Weak nuclear force


Units of Physical Quantities:

There are different types of physical unit of different quantities based on their different needs, some of these units are discussed below:

FPS or British Engineering system

CGS or Gaussian system

MKS system

International system (SI) of units.


MCQ Based on Physical World and Measurement

1. Unification of weak nuclear force and electromagnetic force is given by:

  1. J.C Bose

  2. Lenoir

  3. Abdus Salam

  4. R.A Millikan

Answer: Abdus Salam


2. A refrigerator is a base on the principle of:

  1. Law of thermodynamics

  2. Bernoulli’s principle

  3. Conversion of electrical energy into heat energy

  4. Laws of motion

Answer: Law of thermodynamics


3. Which of the following is not a type of electromagnetic force:

  1. Tension

  2. Friction

  3. Upthrust of liquid

  4. The force between earth and moon

Answer: force between earth and moon


4. Which of the following is not a fundamental law of nature:

  1. Conservation of mechanical energy 

  2. Conservation of change

  3. Conservation of linear momentum

  4. Conservation of angular momentum

Answer: Conservation of mechanical energy


5. Alber Einstein was awarded the Nobel prize for:

  1. Theory of relativity

  2. Conservation of linear momentum 

  3. Photoelectric effect

  4. All

Answer: Photoelectric effect


6. The person, who was given the Nobel prize twice is:

  1. Madam Curie

  2. Albert Einstein

  3. Max Planck

  4. Newton

Answer: Madame Curie


7. Which of the following is the weakest force in nature:

  1. Weak nuclear force

  2. Gravitational force

  3. Electromagnetic force

  4. Strong nuclear force

Answer: Gravitational force


8. Mediating particle in electromagnetic force is:

  1. Gluon

  2. Boson

  3. Gravitation

  4. Photon

Answer: Photon


9. Radio and television act on the principle of:

  1. Propagation of electromagnetic waves

  2. Propagation of X-rays

  3. Solar cell

  4. Optical fiber

Answer: Propagation of electromagnetic waves


10. Which of the following system of units is not based on unit of mass, length and time alone:

  1. S.I

  2. MKS

  3. FPS

  4. CGS

Answer: S.I


11. Which of the following quantity is unitless:

  1. Velocity gradient

  2. Pressure gradient

  3. Displacement gradient

  4. Force gradient

Answer: Displacement gradient


12. Which of the following do not have dimension of force:

  1. Potential energy

  2. Energy gradient

  3. Weight

  4. Rate of change of momentum

Answer: Potential gradient


13. Which of the following is incorrect statement:

  1. A dimensionally correct statement may be equal.

  2. A dimensionally correct statement may be incorrect.

  3. A dimensionally incorrect statement may be correct.

  4. A dimensionally incorrect statement is incorrect.

Answer: A dimensionally incorrect statement may be correct.


14. A unitless quantity:

  1. Does Not exists

  2. Always has a non zero dimension

  3. Never has a non zero dimension

  4. May have a non zero dimension

Answer: Never has a non zero dimension


15. Two quantities are given in which one of which is a vector and another one is a scalar having the same dimensional formula are:

  1. Work and energy

  2. Torque and work

  3. Impulse and momentum

  4. Power and pressure

Answer: Torque and work


16. Which fundamental unit has same power in the dimensional formula of surface tension and viscosity is:

  1. Mass

  2. Length

  3. Time

  4. None

Answer: Mass


17. Temperature can be expressed as a derived quantity in terms of which of the following:

  1. Length and mass

  2. Mass and time

  3. Length, time and mass

  4. In terms of none of these

Answer: In terms of none of these


18. Density of wood is 0.5 g/ cc in the CGS system of units. The corresponding value in MKS unit is:

  1. 500

  2. 5

  3. 0.5

  4. 5000

Answer: 500


19. Which of the following is not the unit of time: 

  1. Microsecond

  2. Leap year

  3. Lunar months

  4. Parallactic second

Answer: Parallactic second


20. Which of the following the smallest unit:

  1. Millimeter

  2. Angstrom

  3. Fermi

  4. Metre

Answer: Fermi


21. Zero error of an instrument introduces:

  1. Systematic error

  2. Random errors

  3. Both

  4. None

Answer: Systematic error


22. Which of the following does not have the same unit as others:

  1. Watt-second

  2. Kilowatt-hour

  3. eV

  4. J-second

Answer: Watt-second


23. ‘Parsec’ is the unit of:

  1. Time

  2. Distance

  3. Frequency

  4. Angular acceleration

Answer: Time


24. The ration of the dimension Planck’s constant and that of the moment of inertia is the dimension of:

  1. Velocity

  2. Angular momentum

  3. Time

  4. Frequency

Answer: Time


25. Which of the following five physical parameters have the same dimension:

  1. Energy density

  2. Refractive index

  3. Dielectric constant

  4. Young’s modulus

  5. Magnetic field

Answer: A and D