Work done is independent of the path followed by the body

Work done depends only on the vertical distance separating the initial and the final position of the body 

Work done depends on the path followed by the body 

Work done is zero if the body is displaced horizontally to the force of gravity

Pressure has magnitude as well as direction: 

As we go deeper in a liquid, the pressure decreases 

Action and reaction forces act on the same object 

Pascal and N/m² represent the same unit  

1 nm 

10 nm

100 nm

300 nm 

larger focal length and larger aperture

larger focal length and smaller aperture 

smaller focal length and larger aperture

smaller focal length and smaller aperture