Question
Question: The correct relation between joule and erg is: \(\left( A \right)1J={{10}^{-5}}erg\) \(\left( B ...
The correct relation between joule and erg is:
(A)1J=10−5erg
(B)1J=105erg
(C)1J=10−7erg
(D)1J=107erg
Solution
Erg and Joule both are the units for work done. Joule is the amount of work done by applying a force of one newton for a distance of 1m while erg is the amount of work done by applying force of one dyne for distance of 1cm.
Formula used: The work done of on any object can be calculated by: W=F∗d
Where F- force applied on the object
d- distance
Complete step by step answer:
erg is the unit for work done in the CGS base units, i.e. gram centimetre-squared.
So,
1joule = 1N×1m
1J=1s21kg×1m×1m
1J=1s21000g×100cm×100cm1J=107erg
So, the correct answer is “Option D”.
Additional Information: Joule is defined as the SI unit of work or energy, adequate to the work done by a force of one newton when its point of application moves one metre within the direction of action of the force, like one 3600th of a watt-hour. Work done by a force on a body are often positive, negative and zero i.e.,
(a) Work done is positive: - Force is within the same direction as displacement for instance work done by force for pushing a block of mass m.
(b) Work done is negative: - Force is opposite to the displacement for instance when a body slides on level work done by frictional forces on the body is negative as frictional force always acts opposite to displacement of the body.
Note: Unit of work done in any system of units is adequate to the unit of force multiplied by the unit of distance. In SI system International unit of work is 1Nm and is said Joule(J). Thus,
1J=1Nm
In CGS system unit is erg
1erg=1dyne−cm