Question
Differentiate between myopia and hypermetropia. What type of spectacles should be worn by a person having the defects of myopia as well as hypermetropia? How does it help?

Answer

In myopia, a person can see nearby objects clearly but cannot see distant object clearly. In hypermetropia, a person can see distant objects clearly but cannot see nearby objects clearly. A person having the defects of myopia as well as hypermetropia should wear spectacles having bifocal lenses in which upper part consists of concave lens and lower part consists of convex lens. The upper part corrects myopia and the lower part corrects hypermetropia.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

What are symptoms of diseases like night blindness, rickets, beriberi, neuritis, pellagra, anaemia, scurvy?
Sketch, labell and classify: Wall Lizard
The following diagram shows a part of the periodic table in which the elements are arranged according to their atomic numbers.
(The letters given here are not the chemical symbols of the elements):
a
3
b
4
 
c
5
d
6
e
7
f
8
g
9
h
10
i
11
j
12
 
k
13
l
14
m
15
n
16
o
17
p
18
  1. Which element has a bigger atom, a or f?
  2. Which element has a higher valency, k or o?
  3. Which element is more metallic, i or k?
  4. Which element is more non-metallic, d or g?
  5. Select a letter which represents a metal of valency 2.
  6. Select a letter which represents a non-metal of valency 2.
Write short note: Land-filling sites.
Explain the construction and working of the following. Draw a neat diagram and label it : Electric Generator (AC)
The flask-shaped organ A at the centre of a flower is surrounded by a number of little stalks B having swollen tops which lie just inside the ring of petals.
  1. Name A. What are the various parts of A?
  2. Which part of A contains gametes?
  3. Name B. What is the swollen top of B known as?
  4. What does the swollen top of b contain?
  5. Out of A and B, which one is (i) male part, and (ii) female part of the flower?
Write all the capital letters of the alphabet which look the same in a plane mirror.
What is esterification and give its uses?
State the rules used for drawing ray diagrams for the formation of an image by a convex lens.
(marginal, array, cell, panel, string, current, power station, potential difference).
Many solar panels are connected in series and in parallel to generate required ………… and ……… Solar …………. is the basic unit in solar electric plant. Many solar cells come together to form a solar …………… Many solar panels connected in series form a solar ………., and many solar strings connected in parallel form a solar …………. As we can obtain as much electrical power as needed, they are used in applications which need ……….. power (e.g. calculators that run on solar energy) to ……….. of MW capacity.