### Physics - Units & measurement

#### 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