Q. 1. List any two factors which affect the rate of a chemical reaction. (1)
Q. 2. Name the primary colours of light. (1)
Q. 3. Out of the two, a toaster of 1kW and an electric heater of 2 kW, which has a greater resistance? (1)
Q. 4. Why is alumina dissolved in molten cryolite during its electrolytic reduction? (1)
Q. 5. A calcium compound which is a yellowish white powder is used as a disinfectant and also in textile industry. Name the compound. Which gas is released when this compound is left exposed to air? (2)
Q. 6. Draw a labelled ray diagram to locate the image of an object formed by a convex lens of focal length 20 cm when the object is placed 30 cm away from the lens. (2)
Q. 7. Choose the metal (from the list given below) which can displace zinc from zinc sulphate solution—Lead, Copper, Magnesium, Silver. Write the equation of the chemical reaction involved. (2)
Q. 8. Why is a satellite lifted to a height of about 200 km from the ground before giving it a horizontal push? What is the minimum velocity required to launch an artificial satellite in an orbit around the earth? (2)
Q. 9. In the circuit shown below calculate:
Q. 12. What are seismic waves? How do they help in the study of the internal structure of the Earth? Name the three layers of the Earth. (3)
Q. 13. What is meant by allotropy? Mention two allotropes of sulphur. What is the cause of their different shapes? Name the gas evolved when sulphur reacts with (3)
Q. 15. What is biogas? How can biogas be obtained? Why is the use of biogas obtained from cow-dung advised in preference to burning of cow-dung cakes?(3)
Q. 17. Name the type of bond that joins the nitrogenous bases of the two strands of a DNA. (1)
Q. 18. List two functions performed by ovaries in a hit man female. (1)
Q. 19. Name the gas produced on
What is the cause of acid rain? Write its two harmful effects.
Q. 20. How are the following effective in controlling particulate emissions present in air?
Q. 21. What is vegetative propagation? When is it used? Name three methods of vegetative propagation. (3)
Q. 22. Explain the role of the following in the process of digestion in the human body:
Draw a diagram of the human respiratory system showing larynx, tracheae, primary bronchus and lungs.
Q. 23. How does blood circulate between lungs and heart in human beings? Give two functions of lymph in human body. (3)