Magnetic Effects of Electric Current — Science STD 10 — Question

Write the importance of ciliary muscles in the human eye. Name the defect of vision that arises due to gradual weakening of the ciliary muscles in old age. What type of lenses are required by the persons suffering from this defect to see the objects clearly?
Akshay, sitting in the last row in his class, could not see clearly the words written on the blackboard. When the teacher noticed it, he announced if any student sitting in the front row could volunteer to exchange his seat with Akshay. Salman immediately agreed to exchange his seat with Akshay. He could now see the words written on the blackboard clearly. The teacher thought it fit to send the message to Akshay’s parents advising them to get his eyesight checked.
In the context of the above event, answer the following questions:

1. Which defect of vision is Akshay suffering from? Which type of lens is used to correct this defect?
2. State the values displayed by the teacher and Salman.
3. In your opinion, in what way can Akshay express his gratitude towards the teacher and Salman?

A certain form of energy is available due to the difference in the temperature of water at the surface of the ocean and its deeper levels.

1. Name the form of energy.
2. Is this energy ultimately derived from the sun or not?
3. Explain how this form of energy can be converted into electricity.
4. What is the minimum temperature difference in water at the surface of ocean and its deeper level which is required to operate power plants based on this energy?

In the following crosses write the characteristics of the progeny.

	Cross	Progeny
a.	RRYY × RRYY Round, yellow Round, yellow	..............
b.	RrYy × RrYy Round, yellow Round, yellow	..............
c.	rryy × rryy wrinkled, green wrinkled, green	..............
d.	RRYY × rryy Round, yellow wrinkled green	..............

The transport system in plants consists of two kinds of tissues X and Y. The tissue X is made up of living cells and consists of two components A and B. The component A has tiny pores in its end walls and contains only cytoplasm but no nucleus. On the other hand, component B has cytoplasm as well as nucleus. The tissue Y is made up of dead cells and consists of two components C and D. The component C has open ends whereas component D does not have open ends. In flowering plants, either only C or both C and D transport water but D is the only water conducting tissue in non - flowering plants.

1. What is (i) tissue X, (ii) component A and (iii) component B?
2. What is (i) tissue Y, (ii) component C and (iii) component D?

Name the hormones secreted by the following endocrine glands:

1. Thyroid gland.
2. Parathyroid glands.
3. Pancreas.
4. Adrenal glands.

What is meant by:

1. Displacement reaction, and
2. Double displacement reaction? Explain with the help of one example each.

Identify the compound X on the basis of the reactions given below. Also, write the name and chemical formula of A, B and C.

The stem of a fruit tree X fixed in soil is cut in a slanting way. The upper part of stem of another fruit tree Y of different variety of same species is also cut in a slanting way. The cut stem of tree Y, without roots but having some leaves, is placed over the rooted cut stem of tree X in such a way that their cut surfaces fit together properly. While joining the two cut stems, care is taken to make sure that the layer Z of one cut stem is in contact with layer Z of the other cut stem. The joint of cut stem is The stem of a fruit tree X fixed in soil is cut in a slanting way. The upper part of stem of another fruit bound tightly with a piece of cloth and covered properly with polythene. Soon the cut heals and the two stems grow together and become one fruit tree producing leaves, flowers and fruits.

1. What is the name of this method of producing plants or trees?
2. What name is given to the cut stem of tree X having roots?
3. What name is given to the cut stem of tree Y which has no roots but has some leaves?
4. Name the layer Z.
5. Why should the layer Z of one cut stem be in contact with the layer Z of the other cut stem?
6. Name any four fruit trees which are usually bred by this technique.
7. State any one advantage of producing fruit trees by this technique.

Give one example each of a chemical reaction characterised by:

1. Evolution of a gas.
2. Change in colour.
3. Formation of a precipitate.
4. Change in temperature.
5. Change in state.

What are the different techniques of water harvesting?