Question

physics only question no. 2 and no. 4 please

Answer 1

Calculation of focal length and powerof correcting lens in hypermetropia: Let y = distance of the near point N' from the defective eye. Now, the nearpoint N of the normal eye is atdistance D = 25 cm. The object placed at N forms its virtual image at N' due to the convex lens used for correction of the defect.