Question

Define :

i) Focus ii) Focal length iii) Radius of curvature iv) Principal axis
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Answer 1

Answer:

Force is a push or a pull that changes or tends to change the state of rest or uniform motion of an object or changes the direction or shape of an object. It causes objects to accelerate. SI unit is Newton.

Answer 2

Answer:

Focus- To give all your attention to something.

Focal length- The distance between the centre of a mirror or a lens and it's focus.

Radius of curvature - The radius of a circle which touches a circle which touches a curve at a given point and curvature at that point.

Principal axis- Each of three mutually perpendicular axis in a body about which the moment of inertia is at a maximum.