Units And Measurements CBSE Questions & Answers

Units And Measurements

This is Physics Class 11 Units and Measurements CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
Physical quantities are
  • A
    quantities such as pounds, dollars and rupees
  • B
    quantities such as kilos, pounds and gallons
  • C
    quantities such as degrees, radians and steradians
  • D
    quantities such as length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity
    Correct
2
Measurement of a physical quantity is essentially the
  • A
    process of observing the physical quantity
  • B
    process of comparing with a standard using an instrument
    Correct
  • C
    process of taking readings on an instrument
  • D
    process of subdividing the physical quantity
3
Fundamental or base quantities are arbitrary. In SI system these are
  • A
    length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity
    Correct
  • B
    as length, mass, time, electric charge, thermodynamic temperature, amount of substance, and luminous intensity
  • C
    length, force, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity
  • D
    length, mass, force, electric current, thermodynamic temperature, amount of substance, and luminous intensity
4
Unit for a fundamental physical quantity is
  • A
    the smallest measurable value of the physical quantity
  • B
    defined as best of various reference standards
  • C
    defined as average various reference standards
  • D
    reference standard for the physical quantity
    Correct
5
In SI system the fundamental units are
  • A
    meter, Newton, second, ampere, Kelvin, mole and candela
  • B
    meter, kilogram, second, ampere, Kelvin, mole and lux
  • C
    meter, kilogram, second, coulomb, Kelvin, mole and candela
  • D
    meter, kilogram, second, ampere, Kelvin, mole and candela
    Correct
6
Derived units
  • A
    are units of physical quantity that cannot be expressed as multiples of fundamental physical quantities
  • B
    are units of physical quantity that can be expressed as a combination of fundamental physical quantities
    Correct
  • C
    are units of physical quantity that can be expressed as multiples of fundamental physical quantities
  • D
    are units of physical quantity that cannot be expressed as a combination of fundamental physical quantities
7
Joule is the SI unit of
  • A
    work
    Correct
  • B
    force
  • C
    acceleration
  • D
    power
8
Newton is the SI unit of
  • A
    force
    Correct
  • B
    acceleration
  • C
    power
  • D
    work
9
The least count of any measuring equipment is
  • A
    None of these
  • B
    the smallest range in any instrument
  • C
    the smallest reading on the instrument
  • D
    the smallest quantity that can be measured using that instrument
    Correct
10
Resolution is
  • A
    a measure of the systematic errors
  • B
    None of these
  • C
    a measure of the bias in the instrument
  • D
    the smallest amount of input signal change that the instrument can detect reliably
    Correct
11
If \(\theta \) is the parallax angle of a planet at a distance 'D', when observed from two different positions on the Earth, separated by distance 'b', the expression for 'D' is
  • A
    \({b \over \theta }\)
    Correct
  • B
    \({{2b} \over \theta }\)
  • C
    \({\theta \over {2b}}\)
  • D
    \({\theta \over b}\)
12
Absolute error of the measurement is
  • A
    the difference between two individual measurements and their mean
  • B
    the difference between the individual measurement and the true value of the quantity squared.
  • C
    the difference between the individual measurement and the true value of the quantity
    Correct
  • D
    the difference between the individual measurement and the true value of the quantity cubed.
13
The arithmetic mean of all the absolute errors \(\Delta {{\rm{a}}_{{\rm{mean}}}}\) is given by
  • A
    \({\rm{2}}\Delta {{\rm{a}}_{{\rm{mean}}}} = {\rm{ }}\left( {\left| {\Delta {{\rm{a}}_{\rm{1}}}} \right| + \left| {\Delta {{\rm{a}}_{\rm{2}}}} \right| + \left| {\Delta {{\rm{a}}_{\rm{3}}}} \right| + ... + {\rm{ }}|\Delta {{\rm{a}}_{\rm{n}}}|} \right)/{\rm{n}}\)
  • B
    \(\Delta {{\rm{a}}_{{\rm{mean}}}} = {\rm{ }}\left( {\left| {\Delta {{\rm{a}}_{\rm{1}}}} \right| + \left| {\Delta {{\rm{a}}_{\rm{2}}}} \right| + \left| {\Delta {{\rm{a}}_{\rm{3}}}} \right| + ... + {\rm{ }}|\Delta {{\rm{a}}_{\rm{n}}}|} \right)\)
  • C
    \(\Delta {{\rm{a}}_{{\rm{mean}}}} = {\rm{ 2}}\left( {\left| {\Delta {{\rm{a}}_{\rm{1}}}} \right| + \left| {\Delta {{\rm{a}}_{\rm{2}}}} \right| + \left| {\Delta {{\rm{a}}_{\rm{3}}}} \right| + ... + {\rm{ }}|\Delta {{\rm{a}}_{\rm{n}}}|} \right)/{\rm{n}}\)
  • D
    \(\Delta {{\rm{a}}_{{\rm{mean}}}} = {\rm{ }}\left( {\left| {\Delta {{\rm{a}}_{\rm{1}}}} \right| + \left| {\Delta {{\rm{a}}_{\rm{2}}}} \right| + \left| {\Delta {{\rm{a}}_{\rm{3}}}} \right| + ... + {\rm{ }}|\Delta {{\rm{a}}_{\rm{n}}}|} \right)/{\rm{n}}\)
    Correct
14
The relative error is given by
  • A
    \(Relativeerror = {{\Delta {a_{mean}}} \over {{a_{mean}}}}\)
    Correct
  • B
    \(Relativeerror = {{2\Delta {a_{mean}}} \over {{a_{mean}}}}\)
  • C
    \(Relativeerror = {{\Delta {a_{mean}}} \over {2{a_{mean}}}}\)
  • D
    \(Relativeerror = {{\Delta {a_{mean}}} \over {1.2{a_{mean}}}}\)
15
Percentage error δa is given by
  • A
    \(\delta {\rm{a }} = {\rm{ }}\left( {\Delta {{\rm{a}}_{{\rm{mean}}}}/{{\rm{a}}_{{\rm{mean}}}}} \right)\) 200\(\% \)
  • B
    \(\delta {\rm{a }} = {\rm{ }}\left( {\Delta {{\rm{a}}_{{\rm{mean}}}}/{{\rm{a}}_{{\rm{mean}}}}} \right)\)70\(\% \)
  • C
    \(\delta {\rm{a }} = {\rm{ }}\left( {\Delta {{\rm{a}}_{{\rm{mean}}}}/{{\rm{a}}_{{\rm{mean}}}}} \right)\)100\(\% \)
    Correct
  • D
    \(\delta {\rm{a }} = {\rm{ }}\left( {\Delta {{\rm{a}}_{{\rm{mean}}}}/{{\rm{a}}_{{\rm{mean}}}}} \right)\) 80\(\% \)