Physics for Defence Warriors set 1 ( NDA / CDS / AFCAT )

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• 0 Questions answered incorrect
• 15 Questions unattempted

• 1

  1. Which one of the following is a vector quantity?

   

  • A

    A.Momentum

     

  • B

    B.Pressure

     

  • C

    C.Energy

     

  • D

    D.Work

     

  Explanation

  Momentum is a vector quantity, whereas pressure, energy and work are scalar quantities. A vector quantity in physics is characterised by both magnitude and direction. Momentum is calculated as the product of an object's mass and its velocity, considering the direction of motion.
  
   

• 2

  2. Which of the following is not a vector quantity?

   

  • A

    A.Displacement

     

  • B

    B.Velocity

     

  • C

    C.Force

     

  • D

    D.Volume

     

  Explanation

  Volume is a scalar quantity while displacement, velocity and force are vector quantities. Volume doesn't have any direction. It only requires a numerical value to describe the amount of space which an object occupies, without any consideration of orientation or vector properties.

• 3

  3. Which of the following is a vector quantity ?

   

  • A

    A.Time

     

  • B

    B.Speed

     

  • C

    C. Displacement

     

  • D

    D. Distance

     

  Explanation

  Displacement is a vector quantity whereas time, speed and distance are scalar quantities. Displacement represents change in position of an object in certain direction. It is characterised by both magnitude and direction, making it different from distance, which is scalar quantity.

• 4

  4. Which one of the following is a scalar quantity?

   

  • A

    A.Force

     

  • B

    B.Pressure

     

  • C

    C.Velocity

     

  • D

    D.Acceleration

     

  Explanation

  Pressure is a scalar quantity whereas, force, acceleration and velocity are vector quantities. Pressure is defined as the force per unit area. Pressure doesn't have specific direction, it's unit is .

• 5

  5. Which of the following is a fundamental physical quantity?

   

  • A

    A.Force

     

  • B

    B.Velocity

     

  • C

    C.Electric current

     

  • D

    D.Work

     

  Explanation

  Among the given options, electric current is a fundamental physical quantity. In science, af] physical quantities are represented in terms of length, mass, time, electric current, luminous intensity and temperature etc. These quantities are called fundamental quantities.

• 6

  6. In international system of measurement, the 'kelvin' is the unit of

   

  • A

    A.mass

     

  • B

    B.temperature

     

  • C

    C.electric current

     

  • D

    D.air  

     

  Explanation

  In international system of measurement, the 'kelvin' is the unit of temperature.
  The SI unit of mass is kilogram (kg). The SI unit of electric current is ampere. However, air is the mixture of gases that makes up the earth's atmosphere.

• 7

  7. The unit of work is

   

  • A

    A.joule

     

  • B

    B.newton

     

  • C

    C.watt

     

  • D

    D.dyne

     

  Explanation

  The unit of work is joule.
  Work done by a force on a body is equal to the product of force and displacement in the direction of force.
  Work done Force Displacement
  Unit of work Joule
  Newton is the unit of force, watt is the unit of power and dyne is the unit of force in CGS system.

• 8

  8. Which one of the following is not correctly matched?

  • A

    (A) Decibel

    - Unit of sound intensity

  • B

    (B) Horsepower

    - Unit of power

  • C

    (C) Nautical miles

    - Unit of naval distance

  • D

    (D) Celsius

    - Unit of heat

  Explanation

  Pair (d) is not correctly matched because celsius is the unit of temperature. Whereas, heat is a form of energy therefore its SI unit is also joule.

• 9

  9. 'Joule' is related to energy in the same way as 'pascal' is related to

   

  • A

    A.mass

     

  • B

    B.pressure

     

  • C

    C.density

     

  • D

    D.purity

  Explanation

  'Joule' is related to energy in the same way as 'pascal' is related to pressure.
  Joule is the SI unit of energy and pascal is the SI unit of pressure.

• 10

  10. Which one of the following quantities does not have unit ?

   

  • A

    A.Stress

     

  • B

    B.Force

     

  • C

    C.Strain

     

  • D

    D.Pressure

     

  Explanation

  Strain is the ratio of two quantities having same unit, hence it does not have any unit.
  Unit of stress, force and pressure are and , respectively.

• 11

  11. Pascal is a unit of measuring

   

  • A

    A.humidity

     

  • B

    B.pressure

     

  • C

    C.rainfall

     

  • D

    D.temperature

     

  Explanation

  Pascal is a unit of measuring pressure.

  

• 12

  12. What is the unit of pressure?

   

  • A

    A.Newton/sq. metre

     

  • B

    B.Newton-metre

     

  • C

    C.Newton

     

  • D

    D.Newton/metre

     

  Explanation

  Newton/sq. metre is the unit of pressure

  

  Unit of pressure

• 13

  13. Ohm-metre is unit of

   

  • A

    A.resistance

     

  • B

    B.conductance

     

  • C

    C.resistivity

     

  • D

    D.charge

     

  Explanation

  Ohm-metre is unit of resistivity.
  Since resistivity,

• 14

  14. The unit of power is

   

  • A

    A.hertz

     

  • B

    B.volts

     

  • C

    C.watt

     

  • D

    D.neutron

  Explanation

  The unit of power is watt.

  

• 15

  15. Frequency is measured in

  • A

    A.hertz

     

  • B

    B.metre/second

     

  • C

    C.radian

     

  • D

    D.watt

     

  Explanation

  Frequency is measure in hertz (Hz). 1 hertz frequency is equal to one oscillations per second.