Subject: Science
Class X
Time Allowed: 3 hours
Max. Marks: 60
General Instructions:
- All questions are compulsory
- Write down the correct answer for the objective type questions (MCQs)
- Internal choice has been provided in essay type questions.
Section – A (Physics)
1. The change in focal length of an eye lens is caused by the action of the
a) Pupil b) Retina c) Ciliary muscles d) Iris
2. Which of the following lenses would you prefer to use whole reading small letters found in dictionary?
a) A convex lens of focal length 50 cm b) A concave lens of focal length 50 cm
c) A convex lens of focal length 5 cm d) A concave lens of focal length 5 cm
3. An electric bulb is rated 220V and 100W. When it is operated in 110V, the power consumed will be
a) 100 W b) 75 W c) 50 W d) 25 W
4. Lens formula is –
a) 1/v + 1/u = 1/f b) 1/u – 1/v = 1/f c) 1/v – 1/u = 1/f d) all of the above
Very short Answers
5. Find the focal length of a lens of power -2.0D. What type of lens is this?
6. Why the sun appears reddish early in the morning?
7. a) Why are coils of electric toasters & electric irons made of an alloy rather than a pure metal?
b) Define Ohm’s Law?
Short Answers
8. What is refraction? What happens when a ray of light enters from a rarer medium to a denser medium? Write the laws of refraction.
9. a) On what factors does the resistance of a conductor depend?
b) Show how you would connect three resistors each of resistance 6 ohm, so that the combination has a resistance of:
i) 9 ohm b) 4 ohm
OR
a) An object 5 cm in length is held 25 cm away from a converging lens of focal length 10 cm. Draw the ray diagram and find the position, size and nature of the image formed?
b) Why do we prefer a convex mirror as a rear-view mirror in vehicles?
Section – B (Chemistry)
10. A metal which is liquid at room temperature is: –
a) Sodium (Na) b) Mercury (Hg) c) Lead (Pb) d) Potassium (K)
11. A solution turns red litmus blue; its pH is likely to be: –
a) 1 b) 4 c) 5 d) 11
12. The chemical formulae for slaked lime are: –
a) Ca(OH)2 b) CaO c) CaCO3 d) CaCl2
13. How bleaching powder is prepared? Write any two uses of bleaching powder.
14. What do you mean by a precipitation reaction? Explain by giving examples.
15. Aluminium is a highly reactive metal yet it is used to make utensils for cooking. Give reasons.
16. a) Why respiration is considered an exothermic reaction? Explain.
b) Why does distilled water not conduct electricity, whereas rain water does?
17. a) Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4
b) Differentiate between Calcination and Roasting
c) State two ways to prevent rusting of iron.
OR
a) Write the balanced chemical equation for the following reactions:
Aluminium + Copper Chloride — > Aluminium Chloride + Copper
b) What do you understand by electrolytic refining?
c) Name two metals which will displace hydrogen from dilute acids and two metals which will not.
Section – C (Biology)
18. The anther contains: –
a) sepals b) ovules c) carpel’s d) pollen grain
19. The gap between two neurons is called a: –
a) dendrite b) synapse c) axon d) impulse
20. Plant hormone which inhibits growth is: –
a) Cytokinin b) Auxin c) Abscisic acid d) Insulin
21. why is the use of iodised salt advisable?
22. Which part of the brain maintains posture and equilibrium of the body?
23. What are the advantages of sexual reproduction over asexual reproduction?
24. Illustrate the process of Reflex action with an example.
25. How are water and food transported in plants?
26. Draw the structure of female reproductive system. What is the function of primary female sex organs?
27. a) Write down three types of blood vessels. Give one important feature of each.
b) Write a short note on the role of small intestine in digestion of food.
OR
a) Explain process of formation and excretion of urine.
b) What are the three different ways in which glucose is oxidized to provide energy in various organisms?