With what kind of lens can you convert a converging beam of rays into a parallel beam?

With what kind of lens can you convert a diverging beam of rays into a parallel beam?

How can you convert benzene to diphenly?

How can you convert a galvanometer into an ammeter ? Explain with diagrams.

How can you convert a galvanometer into a Voltmeter ? Explain with diagrams.

How can you convert saturated solution into unsaturated solution vice-versa?

An object 5cm in length is held 25cm away from a converging lens of focal length 10cm. Draw the ray diagram and find the position, size and the nature of the image formed.

Under what condition can a convex lens form a virtual image?

Take a sheet of paper. Measure its area. Pile up such sheets of paper of same size to make cuboid. Measure the height of this pile. Find the volumne of the couboid by finding the product of the area of the sheet and the height of this pile of sheets. This activity illustrates the idea that volume of a solid can ve deduce by thsi method also (if the base and top of the solid are congruent and parallel to each other and its edges are perpendicular to the base). Can you think of such objects whose volumne can be found by using this method?