Tricky thought on Gauss's law When the charge enclosed by a gaussian surface is equal to $q/2$ nought shouldnt the number of field lines be equal to half which does not make sense at all.
 A: The number of field lines on a diagram has no quantitative meaning. Electric field lines are simply a useful tool to provide primarily qualitative information on the nature of the electric field. (See below for the information that field line drawings are intended to convey). Consequently, two different diagrams from different authors are likely to show a different number of field lines for the same value of a point charge.
On the other hand, if field lines for two different charges are shown on the same diagram, one of value $q$ and the other $q/2$, the diagram should show twice the number of lines for charge $q$ than $q/2$ because the relative strength of the field for $q$ is twice that of $q/2$.
That said, the field line drawings are typically intended to provide the following information:

*

*Arrows that show the direction of the field at a location. By convention, the direction of the field is the direction of the force that a positive charge would experience if placed in the field. Consequently, it provides information on the nature of the source of the field (positive or negative charge). But it does not provide quantitative information on the amount of charge.


*Line density (lines per unit area) providing information on the relative strength of the field at a location relative to another location.  But it does not provide quantitative information on the actual electric field strength.


*Application of Gauss's law and a Gaussian surface. The field lines may provide information on whether the net charge at within a specific area (or volume) is positive, negative, or zero. But it does not provide information on the actual amount of negative or positive charge.
Hope this helps.
