During refraction of light through the glass slab incident ray and emergent ray are parallel to each other explain

This is because the refractive index of the glass remains the same. Light entering the glass is bent at an  angle and the angle is reversed when the light leaves the  glass. Therefore, while the light leaving the glass will not be in straight line with the light entering the glass, both light beams will be parallel to each other.  

like poles repel so keep pushing north to north and repels funny to see this

hypothesising or postulating