JEE Questions for Physics Units And Measurements Quiz 10 - MCQExams.com

The density of a material in CGS system of units is 4g/cm2. In a system of units in which unit of length is 10cm and unit of mass is 100g, the value of density of material will be
  • 4.00
  • 0.04
  • 0.4
  • 40

Physics-Units and Measurements-93551.png
  • M0LT2
  • M0L2T–4
  • M0LT–3
  • M0L2T–1

Physics-Units and Measurements-93553.png
  • Only numerically correct
  • Only dimensionally correct
  • Both numerically and dimensionally correct
  • Neither numerically nor dimensionally correct
When a wave traverses a medium, the displacement of a particle located at x at a time t is given by y a sin (bt — cx), where a, b and c are constants of the wave. Which of the following is a quantity with dimensions?
  • y/a
  • bt
  • cx
  • b/c
The speed of light (c), gravitational constant (G) and Planck’s constant (h) are taken as the fundamental units in a system. The dimension of time in this new system should be
  • G1/2 h1/2 c–5/2
  • G–1/2 h1/2 c1/2
  • G1/2 h1/2 c–3/2
  • G1/2 h1/2 c1/2
If the constant of gravitation (G), Planck\'s constant (h) and the velocity of light (c) be chosen as fundamental units. The dimension of the radius of gyration is
  • h1/2 c–3/2 G1/2
  • h1/2 c3/2 G1/2
  • h1/2 c–3/2 G–1/2
  • h–1/2 c–3/2 G1/2
X = 3YZ2 find dimension of Y in (MKSA) system, if X and Z are the dimensions of capacity and magnetic field respectively.
  • M–3 L–2 T–4 A–1
  • ML–2
  • M–3L–2T4A4
  • M–3L–2T8 A4

Physics-Units and Measurements-93559.png
  • [M0LT–1]
  • [ML0T–1]
  • [ML–1T0]
  • [M0 L0 T0]

Physics-Units and Measurements-93561.png
  • PV
  • 2)
    Physics-Units and Measurements-93562.png

  • Physics-Units and Measurements-93563.png
  • bP
The speed (v) of ripples on the surfaces of water depends on surface tension (σ), density (ρ), and wavelength (λ). The square of speed (v) is proportional to

  • Physics-Units and Measurements-93565.png
  • 2)
    Physics-Units and Measurements-93566.png

  • Physics-Units and Measurements-93567.png
  • ρλσ
If the dimensions of a physical quantity are given by MaLbTc, then the physical quantity will be
  • Pressure is a = 1, b = –1, c = –2
  • Velocity if a = 1, b = 0, c = –1
  • Acceleration if a = 1, b = 1, c = –2
  • Force if a = 0, b = –1, c = –2

Physics-Units and Measurements-93569.png
  • M0L0T–1
  • M0LT0
  • M0L0T
  • Cannot be represented in terms of M, L and T
The dimensions of couple are
  • ML2T–2
  • MLT–2
  • ML–1T–3
  • ML–2T–2
Out of the following, the only pair that does not have identical dimensions is
  • Angular momentum and Planck's constant
  • Moment of inertia and moment of a force
  • Work and torque
  • Impulse and momentum
Which of the following is dimensionally correct?
  • Pressure = Energy per unit area
  • Pressure = Energy per unit volume
  • Pressure = Force per unit volume
  • Pressure = Momentum per unit volume per unit time
If V denotes the potential difference across the plates of a capacitor of capacitance C, the dimensions of CV2 are
  • Not expressible in MLT
  • MLT–2
  • M2LT–1
  • ML2T–2
Which two of the following five physical parameters have the same dimensions ?
(A) Energy density
(B) Refractive index
(C) Dielectric constant
(D) Young\'s modulus
(E) Magnetic field
  • (A) and (D)
  • (A) and (E)
  • (B) and (D)
  • (C) and (E)
Dimensional formula of capacitance (or farad) is
  • M–1L–2T4A2
  • Ml2T4A–2
  • MLT–4A2
  • M–1L–2T–4A–2
The period of a body under SHM is represented by T = PaDbSc ; where P is pressure, D is density and S is surface tension, The value of a, b and c are

  • Physics-Units and Measurements-93577.png
  • 2)
    Physics-Units and Measurements-93578.png

  • Physics-Units and Measurements-93579.png

  • Physics-Units and Measurements-93580.png
Dimensional formula of Stefan\'s constant is
  • MT–3K–4
  • ML2T–2K–4
  • ML2T–2
  • MT–2L0
  • MT–4L0

Physics-Units and Measurements-93583.png
  • M1L4L–2
  • M2L–2T–1
  • M2L–2T–2
  • M1L–2T–1
Dimensional formula of magnetic flux is
  • ML2T–2A–1
  • ML0T–2A–2
  • M0L–2T–2A–3
  • ML2T–2A3
If P represents radiation pressure, c represents speed of light and Q represents radiation energy striking a unit area per second, then non-zero integers x, y and z such that PxQycz is dimensionless, are
  • x = 1, y = 1, z = –1
  • x = 1, y = –1, z = 1
  • x = –1, y = 1, z = 1
  • x = 1, y = 1, z = 1

Physics-Units and Measurements-93587.png
  • Time
  • Mass
  • Length
  • Force
The pair having the same dimensions is
  • Angular momentum, work
  • Work, torque
  • Potential energy, linear momentum
  • Kinetic energy, velocity
If R and L represent respectively resistance and self inductance, which of the following combinations has the dimensions of frequency ?

  • Physics-Units and Measurements-93589.png
  • 2)
    Physics-Units and Measurements-93590.png

  • Physics-Units and Measurements-93591.png

  • Physics-Units and Measurements-93592.png
ML–1T–2 represents
  • Stress
  • Young's Modulus
  • Pressure
  • All the above three quantities
Dimensions of magnetic field intensity is
  • [M0L–1T0A1]
  • [MLT–1A–1]
  • [ML0T–2A–1]
  • [MLT–2A]
A force F is given by F = at + bt2, where is time. What are the dimensions of a and b ?
  • MLT–3 and ML2T–4
  • MLT–3 and MLT–4
  • MLT–1 and MLT0
  • MLT–4 and MLT1
If the speed of light (c), acceleration due to gravity (g) and pressure (p) are taken as the fundamental quantities, then the dimension of gravitational constant is
  • c2g0p–2
  • c0g2p–1
  • cg3p–2
  • c–1g0p–1

Physics-Units and Measurements-93597.png
  • M1L0T–2
  • M0L1T–1
  • M1L1T–2
  • M1L0T–1
If force (F), length (L) and time (T) are assumed to be fundamental units, then the dimensional formula of the mass will be
  • FL–1T2
  • FL–1T–2
  • FL–1T–1
  • FL2T2
In the relation y = a cos (ωt – kx), the dimensional formula for k is
  • [M0L–1T–1]
  • [M0LT–1]
  • [M0L–1T0]
  • [M0LT]
Position of a body with acceleration \'a\' is given by x = Kamtn, here t is the time. Find dimensions of m and n.
  • m = 1, n = 1
  • m = 1, n = 2
  • m = 2, n = 1
  • m = 2, n = 2
Out of the following pairs, which one does not have identical dimensions
  • Moment of inertia and moment of force
  • Work and torque
  • Angular momentum and Planck's constant
  • Impulse and momentum

Physics-Units and Measurements-93602.png
  • MLT1
  • ML2T–2
  • ML–1T–2
  • ML2T–1
The dimensions of gravitational constant G and the moment of inertia are respectively
  • ML3T–2, ML2T0
  • M–1L3T–2, ML2T0
  • M–1L3T–2, M–1L2T
  • ML3T–2; M–1L2T
Assertion : \'Light year\' and \'Wavelength\' both measure distance.
Reason Both have dimensions of time.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The error in the measurement of radius of the sphere is 0.3%. The permissible error in its surface area is 0.6%.
Reason The permissible error is calculated by the formula
Physics-Units and Measurements-93604.png
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Force cannot be added to pressure.
Reason Because their dimensions are different.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Avogadro number is the number of atoms in one gram mole.
Reason Avogadro number is a dimensionless constant.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.

Physics-Units and Measurements-93606.png
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Parallax method cannot be used for measuring distances of stars more than 100 light years away.
Reason Because parallax angle reduces so much that it cannot be measured accurately.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The graph between P and Q is straight line, when P / Q is constant.
Reason The straight line graph means that P proportional to Q or P is equal to constant multiplied by Q.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.

Physics-Units and Measurements-93693.png

  • Physics-Units and Measurements-93694.png
  • 2)
    Physics-Units and Measurements-93695.png

  • Physics-Units and Measurements-93696.png

  • Physics-Units and Measurements-93697.png
Assertion Out of three measurements l = 0.7 m; l = 0.70 m and l = 0.700 m, the last one is most accurate.
Reason In every measurement, only the last significant digit is not accurately known.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Mass, length and time are fundamental physical quantities.
Reason They are independent of each other.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.

Physics-Units and Measurements-93608.png
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Now a days a standard metre is defined in terms of the wavelength of light.
Reason Light has no relation with length.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.

Physics-Units and Measurements-93610.png
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
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