10 Science Solved Sample Paper 5 – Page 3
Question: 16. (a) List in tabular form two differences between an acid and a base based on their chemical properties.
(b) What do you understand by neutralization reaction? Give two examples to illustrate your answer with equations. 
Answer: (b) When an acid reacts with a base then such reactions are called the neutralisation reactions.
HCl + NaOH → NaCl + H2O
H2SO4 + Mg(OH)2 → MgSO4 + H2O
Question: 17. (1). Describe an activity with diagram to show that a current carrying wire experiences a force when placed in a magnetic field.
(2). Suggest two possible ways to change the direction of force on the rod. 
Question: 18. What are stomata? What function do they perform? With the help of diagram explain opening and closing of stomata. 
Answer: Stomata are small pores in the lower epidermis of the leaves. Stomata helps in the exchange of gases between the leaves of the plants and outside air. Stomata also control the loss of water in the form of vapours through the leaves during transpiration.
Draw the diagram of sectional view of human heart and on it name and label the following parts:
(1). The chamber of the heart that pumps out deoxygenated blood.
(2). The blood vessel that carries away oxygenated blood from the hart.
(3). The blood vessel that receives deoxygenated blood from the lower part of our body.
Using the above table answer the following questions:
(a) Compare the atomic sizes of B & C.
(b) Select the letter / letters which represents alkali metals.
(c) Identify the nature of bonds formed by elements of Group 1 and 14.
(d) What would be the electronic configuration of element F?
(e) How does the metallic character vary on going from left to right in a period? 
Answer: (a) Atomic size of C will be smaller than the atomic size of B.
(b). A & D are alkali metals.
(c) Group 1 elements will form ionic bonds however elements of group 14 will form covalent bonds.
(d) Electronic configuration of F is 2, 4.
(e) Metallic character will decrease on going from left to right in a period.
Explain the trends in the Modern Periodic Table of various properties like valency, atomic size, metallic and non-metallic properties of the atoms of elements.
Question: 20. (1). Give two reasons for avoiding frequent pregnancies by women. 
(2). Explain the following methods of contraception giving one example of each.
(i) Barrier method
(ii) Chemical method
(iii) Surgical method
(1). Neeta needs a lens of power -4.5D for correction of her vision. 
(a) What Kind of defect in vision is she suffering from?
(b) What is the focal length and nature of corrective lens?
(c) Explain with the help of a diagram how this defect can be corrected?
(2). State the functions of each of the following parts of human eye.
(a) Cornea (b) Pupil (c) Iris (d) Retina
Hint: (a) Myopia or near sightedness
(b) f = 1/D, So, f = -1/45 = 0.22 m; Concave lens
An object of height 5 cm is placed 20 cm away from a convex mirror. Its image is formed at a distance of 12 cm behind the mirror. Calculate the focal length of the mirror using mirror formula. Also draw a scale diagram to locate the image. From the diagram, find out the length of the image formed. 
h0 = 5 cm, u = -20 cm, v = +12 cm
As we know, 1/f = 1/v + 1/u ⇒ 1/f = 1/12 – 1/20 = 30 cm; h1 = 3 cm (on measurement)