question_answer

Saurabh and his family went for an outing. On the way Saurabh's grandfather lost his spectacles. He was facing difficulty in reading book. Saurabh was carrying a magnifying lens carry out a Biology project. He gave it to his grandfather and solved his difficulty.

(i) What qualities are exhibited by Saurabh?

(ii) Previously his grandfather was using spectacles of power \[=-1D\] for distant vision. Now, he also needs to use reading glass of \[+\,0.2.\] Explain it.

Answer:

(i) Respect and concern for his grandfather, presence of mind.

(ii) Previously far point was 100cm. The power of spectacles was \[-1\text{D,}\] i.e. for an object at infinity range is formed at 100cm by length. Ability of accommodation get lost partically in old age.

Near point recedes to 26.3 cm needs converging lens of \[P=+0.2\] from 25cm that is why he needs a converging lens of \[P=+0.2\,\,\text{D}\]