The diagram below shows an object AB kept in front of the lens. The path of one ray coming from the object is shown:

(a) Name the lens L.

(b) Redraw and complete the ray diagram showing the formation of the image.

(c) In which optical instrument, is this kind of image formed?

A uniform meter scale of mass 60 g, carries masses of 20 g, 30 g and 80 g from points 10 cm, 20 cm and 90 cm marks. Where must be the scale hanged with string to balance the scale?

A nucleus ₁₁Na²⁴ emits a β-particle to change into magnesium (Mg).

(a) Write the symbolic equation for the process.

(b) What are numbers 24 and 11 called?

(c) What is the general name of ₁₂²⁴Mg with respect to ₁₁²⁴Na

If a man raises a box of 50 kg mass to a height of 2 m in 2 min, while the other man raises the same box to the same height in 5 min. Compare

(a) the work done and

(b) the power developed by them.