Fundamental quantities - class-VII
Tests knowledge of fundamental quantities, SI units, derived quantities, and dimensional analysis principles in physics
Questions
The SI unit of specific latent heat is
- $Jkg^{-1}K^{-1}$
- $J^{0}K^{-1}$
- $J kg^{-1}$
- $J kgK^{-1}$
The specific heat capacity of water in SI unit is :
- $4.2 Jg^{-1}K^{-1}$
- $42 Jg^{-1}K^{-1}$
- $420 J kg^{-1}K^{-1}$
- $4200 J kg^{-1}K^{-1}$
The SI unit of thermal capacity is ;
- $J\ kg^{-1}\ K^{-1}$
- $J^{-1}\ kg\ K^{-1}$
- $JK^{-1}$
- $J\ kg\ K^{-1}$
Potential is measured in
- joule/coulomb
- watt/coulomb
- newton-second
- none of these
Name the physical quantity related to the following unit : watt.
- $Force$
- $Power$
- $Work$
- $Pressure$
Name the physical quantity related to the following unit : pascal.
- $Force$
- $Pressure$
- $Work$
- $Distance$
Column I gives three physical quantities. Select the appropriate units for these from the choices given in column II. Some of the physical quantities may have more than one choice.
| Column-I | Column - II |
|---|---|
| a) Capacitance | d) Ohm second |
| b) Inductance | e) Coulomb$^{2}$ joule$^{ -1 }$ |
| c) Magnetic induction | f) Coulomb volt$^{ -1 }$ |
| g) Newton (ampere/metre)$^{ -1 }$ | |
| h) Volt second (ampere)$^{ -1 }$ |
- a-e,f; b-d,h; c-g
- a-h; b-d; c-e
- a-e; b-g,h; c-g
- a-e,f; b-d,h; c-d,e
The SI unit of magnetic permeability is
- ${ Am }^{ -1 }$
- ${ Am }^{ -2 }$
- ${ Hm }^{ -2 }$
- ${ Hm }^{ -1 }$
$\left( Coulomb \right) ^{ 2 }{ J }^{ -1 }$ can be the unit of :
- electric resistence
- electric energy
- electric capacity
- electric power
joule is the unit of
- heat
- temperature
- thermometry
- work
How many fundamental units are present in the SI system of units?
- 5
- 6
- 7
- 3
- True
- False
The units which can neither derived from one another nor resolved into any thing more basic are called
- Fundamental unit
- Scale
- Derived unit
- Standard unit
- True
- False
One second is defined to be equal to:
- 1650763.73 periods of krypton clock
- 652189.63 periods of krypton clock
- 1650755.73 periods of cesium clock
- 9, 19, 26, 31, 770 periods of cesium clock
Which of the following are dimensionless quantities,(symbols have their usual meaning)
[$\eta$=viscocity,$\rho$=density,$r$=radius,$k$=thermal conductivity,$c$=heat capacity.]
- $\dfrac{k}{\rho\times c}$
- $\dfrac{\rho \times v \times r}{\eta}$
- Specific gravity
- Rate of change of angle (in radians) of rotation.
Which of the following is dimensionally correct? ($\rho$=density,$\eta$=coefficient of viscosity,$P$=pressure,$S$=surface tension,$r$=radius,$g$=gravitational constant)
- $h=\dfrac{2Scos\theta}{\rho \times rg}$
- $v=\dfrac{P}{\rho}$
- $V=\dfrac{Pr^{4}t}{\eta}$
- none of the above
Consider the following equation which gives a hypothetical physical quantity mutual dynamic constant $\psi$ as,
$\dfrac{2Scos\theta}{\rho \times rg}$+$\dfrac{1}{2\pi}\dfrac{mgl}{I}$
($I$=moment of inertia ,$S$=surface tension,others symbol have usual meanings)
- $\psi$ may exist
- $\psi$ will never exist
- Such physical quantity is a standard result of electromagnetism ,hence it exists.
- none of the above
Which of the following is not the fundamental quantity,
- mass
- length
- velocity
- time
The most basic rule of dimensional analysis is that of dimensional homogeneity. Only commensurable quantities may be
- compared
- equated
- added or subtracted
- all of the above
Light year is a unit of:
- time
- distance
- light
- intensity of light
Which one can be represented as the symbol of time?
- $m$
- $F$
- $t$
- None
The unit of electric field intensity is:
- Newton/ metre
- Coulomb/ newton
- Newton/ coulomb
- Joule/ newton
Among the following indentify the derived quantities.
- Gravitational constant
- Frequency
- Electric charge
- Electric current
The energy which an electron acquires when accelerated, through a potential difference of $1$ volt is called
- $1$ Joule
- $1$ eV
- $1$ erg
- $1$ watt
The Sl unit of length is the meter. Suppose we adopt a new unit of length which equals to $x$ meters. The area 1 $m ^ { 2 }$ expressed in terms of the new unit has a magnitude:
- $x$
- $x ^ { 2 }$
- $\dfrac { 1 } { x }$
- $\dfrac { 1 } { x ^ { 2 } }$
The impulse $J$ required to bring it to rest when it reaches the vertical position.
- Impulse of $m\sqrt {\dfrac {gl}{3}}$ when it is applied horizontally at distance $l$ from pivoted point
- Impulse of $m\sqrt {\dfrac {gl}{3}}$ when it is applied horizontally at distance $\dfrac {l}{2}$ from pivoted point
- Minimum impulse is $m\sqrt {\dfrac {gl}{2}}$ when it is applied at distance $l$ from pivoted point
- If rod is stopped by applying minimum impulse then the is impulse imparted by pivot is $\dfrac {m\sqrt {gl}}{2\sqrt {3}}$
If $10 ^ { 7 }$ era is taken as unit of energy, $10 ^ { 5 }$ dyne as the unit of force, one second as unit of time. what is, the unit of length?
- $1$ $m$
- $10$ $m$
- $100$ $m$
- None
The following quantities which have same directions :
- force, impulse
- impulse, change in momentum
- change in velocity, change in momentum
- All the above
The MKS unit of quantity $\dfrac{\pi \eta r^4}{2}$ is :
- $N s {m}^{2} radian $
- $Ns/m/Radian$
- $Radian/Ns/m$
- $ Ns/m/Radian^2 $
In S.l. system the value of $\epsilon _ { 0 }$
- $1 c ^ { 2 } N ^ { - 1 } m ^ { - 2 }$
- $9 \times 10 ^ { 9 } c ^ { 2 } N ^ { - 1 } m ^ { - 2 }$
- $\cfrac { 1 } { 9 \times 10 ^ { 9 } } c ^ { 2 } N ^ { - 1 } m ^ { - 2 }$
- $\cfrac { 1 } { 4 \pi \times 9 \times 10 ^ { 9 } } c ^ { 2 } N ^ { - 1 } m ^ { - 2 }$
Unit of self inductance is
- $\cfrac { newton\ second }{ coulomb\quad \times \quad ampere } $
- $\cfrac { joule/coubmb\quad \times \quad second }{ ampere } $
- $\cfrac { volt\quad \times \quad metre }{ coulomb } $
- $\cfrac { newton\quad \times \quad metre }{ ampere } $
If $\epsilon ,\phi $ and t stand for permittivity,electric flux and time respectively, then dimensions of $ \epsilon \cfrac{d \phi}{dt}$ is same as that
- Speed
- Current
- Charge
- Potential difference
Which of the following pairs is not matched?
- Coefficient of self-induction : henry
- Magnetic flux : weber
- Electric flux : volt-meter
- Electric capacity : farad-meter
kilowatt-hour is the unit of ____.
- potential difference
- electric power
- electric energy
- charge
Oersted is the unit of
- Intensity of magnetisation
- Magnetic moment
- Magnetic induction
- Magnetic flux
The SI unit of pressure is
- $Newton$
- $Joule$
- $N/m^{2}$
- $Nm$
The damping force on an oscillator is directly proportional to the velocity. The units of constant of proportionality are
- Kg m/s
- Kg $m/s^2$
- Kg/s
- kgs
The unit of permittivity of free space, $ \varepsilon _ o $ is
- $\dfrac {Coulomb} {newton - meter}$
- $ \dfrac {newton - meter^2} { Coulomb ^2} $
- $\dfrac {Coulomb^2}{newton- meter^2} $
- $ \dfrac {Coulomb^2} {(newton-metre)^2}$
In $S = a + bt + ct^{2}, S$ is measured in metres and $t$ is seconds. The unit of $c$ is
- $ms^{-2}$
- $m$
- $m^{-1}$
- None
If the volume of a cube is equal to its surface area in magnitude. Then the volume of the cube is?
- $216$ unit
- $512$ unit
- $64$ unit
- None of these
In the eqn. $\left (P+\dfrac {a}{V^2}\right )(V-b)=$ constant, the unit of $a$ is
- $dyne\times cm^5$
- $dyne\times cm^4$
- $dyne/cm^3$
- $dyne\times cm^2$
Unit of specific resistance is
- $\Omega/m^2$
- $\Omega m^3$
- $\Omega m$
- $\Omega/m$
Which of the following is different from others?
- Speed
- Density
- Force
- Time
Mass is a _________ physical quantity.
- derived
- fundamental
- semi-derived
- valueless
Which of the following physical quantity is different form others ?
- Displacement
- Velocity
- Force
- Kinetic energy
Write the SI unit of the physical quantity having following dimensional formula
$\displaystyle [{ M }^{ 0 }{ L }^{ 2 }{ T }^{ -2 }{ K }^{ -1 }]$.
- $\displaystyle {m} { kg }^{ 2 }{ K }^{ -1 }$
- $\displaystyle {m} ^{2} { kg }^{ 2 }{ T }^{ -1 }$
- $\displaystyle {m} ^{2} { s }^{ -2 }{ K }^{ -1 }$
- $\displaystyle {m} ^{2} { kg }^{ 2 }{ K }^{ -1 }$
Dimensional analysis is the analysis of the relationships between different physical quantities by
- identifying their fundamental dimensions
- units of measure
- tracking these dimensions as calculations or comparisons are performed.
- All of the above
- True
- False
Which one of the following is not a fundamental SI unit?
- Ampere
- Candela
- Newton
- Kelvin
A dimensionless quantity
- never has a unit
- always has unit
- may have a unit
- does not exit
Some physical quantities are given in Column I and some possible SI units in which these quantities may be expressed are given in Column II. Match the physical quantities in Column I with the units in Column II.
| Column I | Column II |
|---|---|
| i. $GM _eM _s$ | a. (volt) (coulomb) (metre) |
| ii. $3RT/M$ | b. $(kilogram)(metre)^3 (second)^2$ |
| iii. $F^2/q^2B^2$ | c. $(meter)^2 (second)^{-2}$ |
| iv. $GM _e/R _e$ | d. $(farad) (volt)^2 (kg)^{-1}$ |
where G is universal gravitational constant; $M _e$ mass of the earth; $M _s$, mass of sun; $R _e$ radius of the earth; R, universal gas constant;T, absolute temperature; M, molar mass, F, force; q, charge; B, magnetic field.
- $i \rightarrow b., ii \rightarrow c.,d., iii \rightarrow c.,d., iv \rightarrow c.,d.,$
- $i \rightarrow a., ii \rightarrow c.,d., iii \rightarrow c.,d., iv \rightarrow c.,d.,$
- $i \rightarrow d., ii \rightarrow c.,d., iii \rightarrow c.,d., iv \rightarrow c.,d.,$
- $i \rightarrow c., ii \rightarrow c.,b., iii \rightarrow c.,d., iv \rightarrow c.,d.,$
Pressure (P), density $\displaystyle (\rho )$ and velocity (V) be taken as fundamental quantities for dimensional analysis.
- True
- False
$S.I$unit of conductivity is
- $siemens / meter$
- $siemens \times meter$
- $meter \times siemens$
- ${m}^{2}/ohm$
Which expression has the same SI base units as pressure?
- $\dfrac{force}{length\times speed}$
- $\dfrac{force}{length\times time}$
- $\dfrac{mass}{length\times (time)^2}$
- $\dfrac{mass\times (time)^2}{length}$