Advanced terms for engineering in physics:

Surface Tension:It is the force per unit length. Force applied on per unit length of surface is called surface tension.

Its formula is surface tension= Force/ length.

Viscosity : Viscosity is also known as fluid friction which one layer of fluid like water or air applies on the other layer to oppose its motion. In actual fluid friction is much less than solid friction.

Conservative Force: The force which is independent of path covered is called conservative force. It means this force depends only on the initial and final point of path and not concerned with what path is used to reach to final point.Example : gravitational force. if body moves upwards gravitational force applies downwards and if body moves downwards still gravitational force applies downwards it doesn't matter how and where the object is moving.

Non conservative force:The force which depends on the path covered is called non conservative force.For example: friction force. if object moves in left direction friction is on right side and vice versa.

Refractive Index:It is the ratio of speed of light in vacuum to speed of light in any medium. Its formula is: u =c/v here c denotes the speed of light in vacuum and v denotes the speed of light in any medium.It doesn't have any unit.

Light year: It the distance covered by light in one year. Its value is 9.46 * 10^12 km.it is the unit of distance but some students are confused by taking it unit of time but is is not like that . it covers the distance so it is the unit of distance only.

Astronomical Unit: The average distance between the centre of sun and earth is equal to one astronomical unit. Its value is 1.496*10^11 m.

Parsec: If we take an arc of 1 Astronomical unit then at which distance ends of arc make an angle of 1 second this distance is equals to one parsec.

1 parsec = 3.08 * 10^16 m.