MODEL PAPER 7 — Science STD 10 — Question

There are two important fuels A and B both of which are extracted from deep inside the earth. Fuel A is a thick, dark, foul smelling liquid whereas fuel B is a black solid. Combustion of both the fuels produces products, C, D, E and F. The product C makes the rainwater only slightly acidic but it is mainly responsible for causing global warming. The product D is neither acidic nor basic. It is harmless and does not affect the environment in any way. Both E and F attack breathing system of humans and are mainly responsible for causing acid rain. In addition to combustion of fuels A and B, the product F is also formed when lightning occurs in the sky.

1. What are (i) fuel A, and (ii) fuel B?
2. Name (i) C (ii) D (iii) E, and (iv) F?
3. What is the process of formation of F during lightning known as?
4. Which fuel is supposed to be exhausted sooner : A or B?
5. Which fuel is mostly used for generating electricity at thermal power plants?

1. Draw a sectional view of the human heart and label on it, Aorta, Right Ventricle and Pulmonary Veins.
2. State the functions of the following components of transport system:

1. Blood.
2. Lymph.

A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits-blood group A or O - is dominant? Why or why not?

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.

What is meant by:

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

Define the term dispersion of white light. Name the colour of light which bends (i) the most, (ii) the least, while passing through a glass prism Draw a ray diagram to Justify your answer.

A and B are two pairs of glands that are present in the human endocrine system. The pair A is found only in females, whereas B is present only in males. Glands A make and secrete two hormones C and D, whereas glands B make and secrete only one hormone E. In addition to hormones, Glands A make gametes F, whereas glands B make gametes G.

1. What are the glands A?
2. What are the hormones C and D?
3. What are the glands B? Name the hormone E.
4. What are the gametes F and G?
5. Which event in the life of males and females is associated with the secretion of the hormones C, D and E?

What are alloys? How are they made? Name the constituents and uses of brass, bronze and solder.

Why does menstruation occur? Describe the menstrual cycle in human females (or women).