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

Write Short note: Fragmantation.
Write all the capital letters of the alphabet which look the same in a plane mirror.
What are the conventions used in writing a chemical equation?
The surface of water in a lake appears green due to a layer of tiny free-floating organisms X on its surface. The lake water also contains organisms like water beetle, fish and tadpole. The sun shines over the lake water and provides energy for the functioning of this lake ecosystem.
  1. What could organisms X be?
  2. Write a food chain comprising of all the four organisms mentioned.
  3. What is the general name of the food chains like the one written above?
  4. Name (i) secondary consumer (ii) producer (iii) tertiary consumer, and (iv) primary consumer, in the above food chain.
  5. If the tertiary consumer gets 0.2 J of energy from the secondary consumer, then how much energy was radiated by the sun to the producer?
What is meant by homologous series?
Draw a figure explaining various terms related to a lens.
Calculate the amount of energy that will be available to big fish in the following food chain, if 10,000 J of energy is available to small algae from the sun:
Small algae —> Zooplankton —> Fish —> Big fish
State one use each of the following metals:
Copper, Aluminium, Iron, Silver, Gold, Mercury
Explain the factors affecting the value of $g.$
A group of students measured the pH of some substances they found in their homes. Their results are given in the following table:
Sabstance pH Sabstance pH
Apples 3.0 Salt 7.0
Baking soda 8.5 Sugar 7.0
Black coffee 5.0 Toothpaste 9.0
Houshold ammonoa 12.0 Vinegar 3.0
Lemon juoce 2.5 Wasimg soda 11.5
Milk 6.0    
  1. What would the students have used to measure the pH?
  2. Which solution is the most acidic (c) Which solution is the most alkaline?
  3. Which solutions are neutral?
  4. Which solution can be used to treat wasp stings?
  5. Which solution can be used to treat bee stings?