MCQz

Measurements

Physics · 11th Class (Intermediate Part 1) · BISE Lahore

70 questions

Tests for this chapter

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Full Book Test

20 questions · Measurements × 1, Force and Motion × 2, Circular and Rotational Motion × 2, Work, Energy and Power × 1, Solids and Fluid Dynamics × 2, Heat and Thermodynamics × 1, Waves and Vibrations × 3, Physical Optics and Gravitational Waves × 1, Electrostatics and Current Electricity × 3, Electromagnetism × 2, Special Theory of Relativity × 1, Nuclear and Particle Physics × 1

Measurements Test

10 questions · Measurements × 10

Sample questions

Showing 20 of 70 questions from this chapter. The full bank is in the chapter test below.

  1. 1

    Which of the following is a base quantity in the SI system?

    • A.Electric current (correct answer)
    • B.Force
    • C.Velocity
    • D.Pressure
    Why: Electric current is one of the seven SI base quantities and its unit is defined independently. Force, velocity and pressure are all derived quantities, because each of them is defined in terms of mass, length and time.
  2. 2

    Which of the following is a derived quantity?

    • A.Mass
    • B.Density (correct answer)
    • C.Length
    • D.Time
    Why: Density is mass per unit volume, so it is defined through the base quantities mass and length. Mass, length and time are themselves base quantities.
  3. 3

    How many base units are there in the International System of Units?

    • A.Three
    • B.Five
    • C.Seven (correct answer)
    • D.Nine
    Why: SI is built on seven base units: metre, kilogram, second, ampere, kelvin, candela and mole. Every other unit is obtained from these by multiplication or division.
  4. 4

    The SI base unit of thermodynamic temperature is the

    • A.degree Celsius
    • B.degree Fahrenheit
    • C.candela
    • D.kelvin (correct answer)
    Why: Thermodynamic temperature is a base quantity and its unit is the kelvin. The degree Celsius is a scale related to it, while the candela measures luminous intensity.
  5. 5

    The SI base unit that measures the amount of a substance, that is the number of particles, is the

    • A.mole (correct answer)
    • B.kilogram
    • C.candela
    • D.ampere
    Why: The mole is the base unit for the amount of a substance. The kilogram measures mass and not the number of particles, which is why a separate base unit is needed for the amount of substance.
  6. 6

    One radian is defined as the ratio of

    • A.area to radius
    • B.arc length to radius (correct answer)
    • C.chord to diameter
    • D.circumference to radius
    Why: One radian is the angle subtended at the centre of a circle by an arc equal in length to the radius, so it is the ratio of arc length to radius. Being a ratio of two lengths it is dimensionless, and SI lists it among derived units.
  7. 7

    The steradian is the SI unit of

    • A.plane angle
    • B.angular velocity
    • C.solid angle (correct answer)
    • D.luminous intensity
    Why: The steradian (sr) measures solid angle, whereas the radian measures plane angle and the candela measures luminous intensity. Both the radian and the steradian are dimensionless derived units.
  8. 8

    One newton expressed in SI base units is

    • A.1 kg m s−11\ \mathrm{kg\,m\,s^{-1}}
    • B.1 kg m2 s−21\ \mathrm{kg\,m^{2}\,s^{-2}}
    • C.1 kg m−1 s−21\ \mathrm{kg\,m^{-1}\,s^{-2}}
    • D.1 kg m s−21\ \mathrm{kg\,m\,s^{-2}} (correct answer)
    Why: Force is mass times acceleration, so 1 N=1 kg×1 m s−2=1 kg m s−21\ \mathrm{N} = 1\ \mathrm{kg} \times 1\ \mathrm{m\,s^{-2}} = 1\ \mathrm{kg\,m\,s^{-2}}. The combination kg m2 s−2\mathrm{kg\,m^{2}\,s^{-2}} is the joule and kg m−1 s−2\mathrm{kg\,m^{-1}\,s^{-2}} is the pascal.
  9. 9

    The unit of work, the joule, can be written in SI base units as

    • A.1 kg m2 s−21\ \mathrm{kg\,m^{2}\,s^{-2}} (correct answer)
    • B.1 kg m s−21\ \mathrm{kg\,m\,s^{-2}}
    • C.1 kg m2 s−31\ \mathrm{kg\,m^{2}\,s^{-3}}
    • D.1 kg m−1 s−21\ \mathrm{kg\,m^{-1}\,s^{-2}}
    Why: Work is force times distance, so 1 J=1 N m=kg m s−2×m=1 kg m2 s−21\ \mathrm{J} = 1\ \mathrm{N\,m} = \mathrm{kg\,m\,s^{-2}} \times \mathrm{m} = 1\ \mathrm{kg\,m^{2}\,s^{-2}}. The combination kg m2 s−3\mathrm{kg\,m^{2}\,s^{-3}} is the watt.
  10. 10

    Pressure is force per unit area. In SI base units, the pascal is therefore equal to

    • A.1 kg m s−21\ \mathrm{kg\,m\,s^{-2}}
    • B.1 kg m−1 s−21\ \mathrm{kg\,m^{-1}\,s^{-2}} (correct answer)
    • C.1 kg m−2 s−21\ \mathrm{kg\,m^{-2}\,s^{-2}}
    • D.1 kg m2 s−31\ \mathrm{kg\,m^{2}\,s^{-3}}
    Why: Pressure is force per unit area, so 1 Pa=1 N m−2=kg m s−2×m−2=1 kg m−1 s−21\ \mathrm{Pa} = 1\ \mathrm{N\,m^{-2}} = \mathrm{kg\,m\,s^{-2}} \times \mathrm{m^{-2}} = 1\ \mathrm{kg\,m^{-1}\,s^{-2}}. The option kg m s−2\mathrm{kg\,m\,s^{-2}} is the newton.
  11. 11

    Electric charge is measured in coulombs. One coulomb written in SI base units is

    • A.1 A s−11\ \mathrm{A\,s^{-1}}
    • B.1 A−1 s1\ \mathrm{A^{-1}\,s}
    • C.1 A s1\ \mathrm{A\,s} (correct answer)
    • D.1 A s21\ \mathrm{A\,s^{2}}
    Why: Electric charge is current multiplied by time, so 1 C=1 A×1 s=1 A s1\ \mathrm{C} = 1\ \mathrm{A} \times 1\ \mathrm{s} = 1\ \mathrm{A\,s}. The inverted form A s−1\mathrm{A\,s^{-1}} would be the ampere per second, not a charge.
  12. 12

    SI does not permit the use of the former CGS units. Which of the following is such a unit?

    • A.litre
    • B.tonne
    • C.electron volt
    • D.erg (correct answer)
    Why: The erg is a CGS unit of energy, like the dyne, gauss, poise and torr, and SI does not allow it. The litre, tonne and electron volt are additional units whose use together with SI is permitted.
  13. 13

    The prefix nano- represents the factor

    • A.10−910^{-9} (correct answer)
    • B.10−610^{-6}
    • C.10−1210^{-12}
    • D.10−1510^{-15}
    Why: Nano- means 10−910^{-9}, as in a nanometre. Micro- is 10−610^{-6}, pico- is 10−1210^{-12} and femto- is 10−1510^{-15}.
  14. 14

    One gigametre is how many times larger than one megametre?

    • A.10210^{2}
    • B.10310^{3} (correct answer)
    • C.10610^{6}
    • D.10910^{9}
    Why: Giga- means 10910^{9} and mega- means 10610^{6}, so their ratio is 109/106=10310^{9}/10^{6} = 10^{3}. Prefixes change in steps of a thousand, and the answer 10910^{9} wrongly compares a gigametre with a metre.
  15. 15

    Which of the following is written correctly?

    • A.1kg
    • B.1k g
    • C.1 kg (correct answer)
    • D.1 kg.
    Why: A space is always left between the value and the unit symbol, and no full stop is placed after a symbol except at the end of a sentence, so 1 kg is correct. In 1kg the space is missing, 1k g splits the symbol, and 1 kg. carries a needless full stop.
  16. 16

    The capacitance of a capacitor is 1×10−12 F1 \times 10^{-12}\ \mathrm{F}. Which is the correct way of writing this value with an SI prefix?

    • A.1 μμF1\ \mathrm{\mu\mu F}
    • B.1 nF1\ \mathrm{nF}
    • C.1 mF1\ \mathrm{mF}
    • D.1 pF1\ \mathrm{pF} (correct answer)
    Why: Compound prefixes such as μμF\mathrm{\mu\mu F} are not allowed, so 10−12 F10^{-12}\ \mathrm{F} is written as 1 pF1\ \mathrm{pF} (pico). A nanofarad is 10−9 F10^{-9}\ \mathrm{F}, a thousand times larger, and a millifarad is 10−3 F10^{-3}\ \mathrm{F}.
  17. 17

    Unit symbols are normally written in lowercase letters. Which unit is the stated exception?

    • A.litre (correct answer)
    • B.metre
    • C.second
    • D.kilogram
    Why: The litre is written with a capital L, for example 1 L, although it is not named after a scientist. The metre, second and kilogram all keep lowercase symbols.
  18. 18

    When a multiple of a base unit is raised to a power, the power applies to the whole multiple. According to this rule, 1 km21\ \mathrm{km^{2}} is equal to

    • A.103 m210^{3}\ \mathrm{m^{2}}
    • B.106 m210^{6}\ \mathrm{m^{2}} (correct answer)
    • C.104 m210^{4}\ \mathrm{m^{2}}
    • D.109 m210^{9}\ \mathrm{m^{2}}
    Why: 1 km2=(103 m)2=106 m21\ \mathrm{km^{2}} = (10^{3}\ \mathrm{m})^{2} = 10^{6}\ \mathrm{m^{2}}. The tempting answer 103 m210^{3}\ \mathrm{m^{2}} wrongly applies the power to the base unit alone.
  19. 19

    Which of the following is the preferred SI way of writing the unit of speed?

    • A.metre/second
    • B.m/s\mathrm{m/s}
    • C.m s−1\mathrm{m\,s^{-1}} (correct answer)
    • D.mps
    Why: SI prefers negative index notation to the solidus, and symbols must never be mixed with unit names, so m s−1\mathrm{m\,s^{-1}} is the correct form. The form metre/second mixes a name with a symbol, and mps is not an SI symbol at all.
  20. 20

    The number 0.0023 written in scientific notation is

    • A.2.3×1032.3 \times 10^{3}
    • B.23×10−423 \times 10^{-4}
    • C.0.23×10−20.23 \times 10^{-2}
    • D.2.3×10−32.3 \times 10^{-3} (correct answer)
    Why: Scientific notation leaves exactly one non-zero digit to the left of the decimal point, so 0.0023 is written as 2.3×10−32.3 \times 10^{-3}. The form 23×10−423 \times 10^{-4} is numerically equal but not in the accepted standard form.
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