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Candela is used to express electric field intensity.

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Important Questions on Units and Measurements

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Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

A physical quantity of the dimensions of length that can be formed out of

c, G

and

\frac{e^{2}}{4 π ε_{0}}

, where [

c

is velocity of light,

G

is universal constant of gravitation,

e

is charge &

ε_{0}

is permittivity of free space]:

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Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

Expression for time in terms of

G

(universal gravitational constant),

h

(Planck constant) and

c

(speed of light) is proportional to:

EASY

Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

Time

(T)

, velocity

(C)

and angular momentum

(h)

are chosen as fundamental quantities instead of mass, length and time. In terms of these, the dimensions of mass would be:

EASY

Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

A, B, C

, and

D

are four different physical quantities having different dimensions. None of them is dimensionless. But we know that the equation

A D = C l n (B D)

holds true. Then which of the combination is not a meaningful quantity?

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Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

The density of a material in

SI

units is

128 kg m^{- 3} .

In certain units in which the unit of length is

25 cm

and the unit of mass is

50 g,

the numerical value of density of the material is:

EASY

Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

In the following

I

refers to current and other symbols have their usual meaning. Choose the option that corresponds to the dimensions of electrical conductivity:

EASY

Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

Planck's constant

(h)

, speed of light in a vacuum

(c)

and Newton's gravitational constant

(G)

are three fundamental constants. Which of the following combinations of these has the dimension of length?

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Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

In the formula

X = 5 Y Z^{2}

X

and

Z

have dimensions of capacitance and magnetic field, respectively. What are the dimensions of

Y

in SI units?

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Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

Let $[\in_{0}]$ denote the dimensional formula of the permittivity of vacuum. If M = mass, L = length, T = time and A = electric current, then :

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Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

If electronic charge

e

, electron mass

m

, speed of light in vacuum

c

and Planck's constant

h

are taken as fundamental quantities, the permeability of vacuum

μ_{0}

can be expressed in units of:

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Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

If Surface tension

(S)

, Moment of Inertia

(I)

and Planck's constant

(h),

were to be taken as the fundamental units, the dimensional formula for linear momentum would be:

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Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

A length - scale

(l)

depends on the permittivity

(ε)

of a dielectric material, Boltzmann constant

k_{B}

, the absolute temperature T, the number per unit volume (n) of certain charged particles, and the charge (q) carried by each of the particles, Which of the following expressions (s) for

l

is (are) dimensionally correct?

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Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

S I

units, the dimensions of

\sqrt{\frac{ϵ_{0}}{μ_{0}}}

is:

HARD

Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

In terms of potential difference

V

, electic current

I

, permittivity

ε_{0}

, permeability

μ_{0}

and speed of light

c

, the dimensionally correct equation(s) is (are)

HARD

Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

Let us consider a system of units in which mass and angular momentum are dimensionless. If the length has a dimension of

L,

which of the following statement (s) is/are correct?

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Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

The force

F

acting on a body of density

d

are related by the reflection

F = \frac{y}{\sqrt{d}}

. The dimensions of

y

are

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Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

Which of the following combinations has the dimension of electrical resistance

(ϵ_{0}

is the permittivity of vacuum and

μ_{0}

is the permeability of vacuum)?

HARD

Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

If energy

(E)

, velocity

(V)

and time

(T)

are chosen as the fundamental quantities, the dimensional formula of surface tension will be___(For surface tension, Force=Surface tension

\times

length)

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Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

Let

L, R, C

and

V

represent inductance, resistance, capacitance and voltage, respectively. The dimension of

\frac{L}{R C V}

S I

units will be:

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Physics>Mechanics>Units and Measurements>Dimensional Formulae and Equations

Parsec is the unit of :

Candela is used to express electric field intensity.

Important Questions on Units and Measurements

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