3
2
9. What are hyper metropia and myopia?
1+1=2
10. Why is very less heat generated in long electrical cables than filaments of
electric bulbs?
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11. List two methods of producing magnetic fields.
1+1=2
Answer the following questions in about 40 - 60 words:
12. What does one mean by exothermic and endothermic reactions? Give
examples
Or
What
is balanced chemical equation? Why should chemical equations be
balanced?
13. Fresh milks has a pH of 6. How do you think the pH will change as it turns into
curd? Explain your answer.
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14. Give reasons:
a. Why do aluminium sheets not corrode easily?
b. Why is copper vessel covered with a green coating in rainy season?
15. Explain the mechanism of the cleaning action of soaps.
What is hydrogenation? What is its industrial application?
6. What are the differences between the transport of materials in xylem and
bloem?
?. Draw the structure of neuron and explain its function
Answers
Answer:
this is your answer
Explanation:
9) A vision condition in which nearby objects are blurry.
Hyperopia is a common vision condition in adults.
Very common
More than 10 million cases per year (India)
Treatable by a medical professional
Requires a medical diagnosis
Lab tests or imaging not required
Chronic: can last for years or be lifelong
For informational purposes only. Consult your local medical authority for advice.
Sources: Apollo Hospitals and others.
Symptoms
Requires a medical diagnosis
People with hyperopia must squint to see nearby objects. Reading, writing, computer work or drawing for long periods of time may cause eye strain and headache.
10)Less heat is generated in long electric cables than in filaments of electric bulbs because the filament has very high resistance whereas electric cables have very low resistance.
11) Some of the methods of producing magnetic field are using permanent magnets, electromagnets and current carrying conductors.
12) reaction in which heat energy is liberated by the reactants is called exothermic reaction. eg: Carbon + Oxygen gives Carbon Dioxide + Q. reaction in which heat energy is absorbed by the reactants is called endothermic reaction. eg: Nitrogen + Oxygen gives 2 nitrous oxide (2NO) - Q.
13) The pH value of milk is 6 since it is acidic in nature. When the milk is converted into curd due to the action of bacteria, lactic acid is formed which is more acidic in nature. Therefore the pH value of the milk is reduced as it turns to curd.
14)Aluminum unlike iron and steel,does not rust or corrode in moist conditions. ... When copper vessel is exposed to air in rainy season, the metal reacts with gases and moisture and atmospheric gases to form a mixture of coppercarbonate and copper hydroxide. This gives a green colour to the surface ofcopper metal.
15)When soap is added to an oily or greasy part of cloth, the hydrocarbon part of soap dissolves in oil, keeping the head away from the oil. Big molecules of oil and soap break by rubbing into small emulsified oil droplets in water, which are washed away by stream of water.
16) The xylem consists of tracheids and vessels, which transport water and minerals to the leaves. The phloem transports the photosynthetic products from the leaf to the other parts of the plant.