JEE Physics - Physics and Measurement

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Question - 1

A small sphere of radius r with a velocity v under streamline conditions in a viscous fluid experiences a retarding force F given by \(F=Kr\vartheta \) where K is a dimensonless constant. The SI system have the dimensions in mass, length and time as

  • A 1, -2, -2
  • B 1, -1, +1
  • C 1, -1, -1
  • D 1, 1, -2

Question - 2

Dimensional formula for electron volt is

  • A MLT2
  • B ML2T-2
  • C ML2T-3
  • D ML-2T-2

Question - 3

Nm2 kg-2 is the SI unit of

  • A Eistein's constant
  • B Boltzmann's constant
  • C Planck's constant
  • D Loschmidt's constant

Question - 4

Which of the following pairs of physical quantities does not have the same dimensions?

  • A Couple and angular momentum
  • B (pressure X Volume) and surface tension
  • C Torque and Impulse
  • D Parsec and Light year

Question - 5

The diminsions of light (or electromagnetic energy) have

  • A -1 in mass
  • B +1 in length
  • C -2 in time
  • D -2 in length

Question - 6

The SI unit of Gravitational field indensity is

  • A ms-2
  • B J kg-1
  • C N kg m-2
  • D kg N-1

Question - 7

Angular velocity is

  • A A scalar
  • B an axial vector
  • C a polar vector
  • D a tensor

Question - 8

Dimension of compressibility of a substance is

  • A +2 in time
  • B +1 in mass
  • C -1 in length
  • D -2 in time

Question - 9

The period of a sample pendulum is calculated for 10 oscillations. If the experiment is repeated for 40 oscillations, the error in the measurement of time period will be reduced by a factor of

  • A \(1\over 4\)
  • B 400
  • C 4
  • D 30

Question - 10

The density of copper is 9 g/cc. In a unit system in which unit length is 5 cm and unit mass is 45 g, the density of copper is

  • A 25
  • B \(81\over 25\)
  • C 1
  • D 625