Medium
Mention the $MKS$ and $CGS$ units of work,define them,and write the dimensional formula of work.
(N/A) The $MKS$ unit of work is the Joule $(J)$.
Definition of Joule: One Joule of work is said to be done when a force of $1 \text{ Newton}$ displaces a body by $1 \text{ metre}$ in the direction of the applied force.
$1 \text{ Joule} = 1 \text{ N} \cdot \text{m} = 1 \text{ kg} \cdot \text{m}^2 \cdot \text{s}^{-2}$.
The $CGS$ unit of work is the erg.
Definition of erg: One erg of work is said to be done when a force of $1 \text{ dyne}$ displaces a body by $1 \text{ cm}$ in the direction of the applied force.
$1 \text{ erg} = 1 \text{ dyne} \cdot \text{cm} = 1 \text{ g} \cdot \text{cm}^2 \cdot \text{s}^{-2}$.
Dimensional formula of work: $[M^1 L^2 T^{-2}]$.
Conversion: $1 \text{ Joule} = 10^7 \text{ erg}$.
Practical units of work/energy:
Definition of Joule: One Joule of work is said to be done when a force of $1 \text{ Newton}$ displaces a body by $1 \text{ metre}$ in the direction of the applied force.
$1 \text{ Joule} = 1 \text{ N} \cdot \text{m} = 1 \text{ kg} \cdot \text{m}^2 \cdot \text{s}^{-2}$.
The $CGS$ unit of work is the erg.
Definition of erg: One erg of work is said to be done when a force of $1 \text{ dyne}$ displaces a body by $1 \text{ cm}$ in the direction of the applied force.
$1 \text{ erg} = 1 \text{ dyne} \cdot \text{cm} = 1 \text{ g} \cdot \text{cm}^2 \cdot \text{s}^{-2}$.
Dimensional formula of work: $[M^1 L^2 T^{-2}]$.
Conversion: $1 \text{ Joule} = 10^7 \text{ erg}$.
Practical units of work/energy:
| erg | $10^{-7} \text{ J}$ |
| Electron volt (eV) | $1.6 \times 10^{-19} \text{ J}$ |
| Calorie (cal) | $4.186 \text{ J}$ |
| Kilowatt hour (kWh) | $3.6 \times 10^6 \text{ J}$ |
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Similar Questions
State whether the following statements are true or false:
$(a)$ $A$ physical quantity can have units but still be dimensionless.
$(b)$ Impulse and the gradient of energy have the same units.
$(c)$ The absolute error in every measurement is equal to the least count of the measuring instrument.
$(a)$ $A$ physical quantity can have units but still be dimensionless.
$(b)$ Impulse and the gradient of energy have the same units.
$(c)$ The absolute error in every measurement is equal to the least count of the measuring instrument.
Medium
View SolutionWhich of the following statements regarding the nature of physical laws is $NOT$ correct?
Out of the following,the only pair that does not have identical dimensions is
Medium
View SolutionMatch List-$I$ with List-$II$.
List-$I$ List-$II$ $(a)$ Torque $(i)$ ${MLT}^{-1}$ $(b)$ Impulse $(ii)$ ${MT}^{-2}$ $(c)$ Tension $(iii)$ ${ML}^{2} {T}^{-2}$ $(d)$ Surface Tension $(iv)$ ${ML} {T}^{-2}$
Choose the most appropriate answer from the options given below:
| List-$I$ | List-$II$ |
| $(a)$ Torque | $(i)$ ${MLT}^{-1}$ |
| $(b)$ Impulse | $(ii)$ ${MT}^{-2}$ |
| $(c)$ Tension | $(iii)$ ${ML}^{2} {T}^{-2}$ |
| $(d)$ Surface Tension | $(iv)$ ${ML} {T}^{-2}$ |
Choose the most appropriate answer from the options given below:
Match the following (Take the relative strength of the strongest fundamental forces in nature as $1$):
$I$ (Fundamental forces in nature) $II$ (Relative strength) $(A)$ Strong nuclear force $(e)$ $10^{-2}$ $(B)$ Weak nuclear force $(f)$ $1$ $(C)$ Electromagnetic force $(g)$ $10^{10}$ $(D)$ Gravitational force $(h)$ $10^{-13}$ $(i)$ $10^{-39}$
The correct match is:
| $I$ (Fundamental forces in nature) | $II$ (Relative strength) |
|---|---|
| $(A)$ Strong nuclear force | $(e)$ $10^{-2}$ |
| $(B)$ Weak nuclear force | $(f)$ $1$ |
| $(C)$ Electromagnetic force | $(g)$ $10^{10}$ |
| $(D)$ Gravitational force | $(h)$ $10^{-13}$ |
| $(i)$ $10^{-39}$ |
The correct match is:
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