Class 10 > PYQ SCIENCE > 2012 > SET A

2012

History 4 Views

Q11
List three problems which arise due to construction of big dams. Suggest a solution for these problems.

Q12
List the products pf combustion of fossil fuels. What are their adverse effects on the environment?

Q13
What is meant by homologous series of organic compounds? Write the chemical formulae of two members of a homologous series and state which part determines the physical properties,
chemical properties, of these compounds.

Q14
Na, Mg and A1 are the elements having one, two and three valence electrons , . respectively. Which of these elements has the largest atomic radius,
is least
reactive? Justify your answer stating reason for each.

Q15
List and explain in brief three methods of contraception.

Q17
List in tabular form two distinguishing features between acquired traits and inherited traits, with one example of each.

Q18
How are fossils formed? Describe, in brief, two methods of determining the age of fossils.

Q19
Ethanol is one of the most important industrial chemicals. It is used in medicine, to synthesize many important compounds, it is an excellent solvent.However, inspite of its benefits it causes many social problems. If a person drinks alcohol regularly, he becomes an alcoholic. Alcohol is non-toxic but it produces physiological effects disturbing brain activity. These persons are also a threat to the lives of others.
(a) Give three reasons in favour and three reasons against ‘alcohol-free world’.
(b) ‘Alcohol drinking should not be potrayed on media.’ Give valid reasons to justify.
(c) As a student what initiative would you take in the concern of “We should condemn
d

Q20
With the help of a ray diagram, state what is meant by refraction of light. State Snell’s law for refraction of light and also express it mathematically.The refractive index of air with respect to glass is 2/3 and the refractive index of water with respect to air is 4/3. If the speed of light in glass is 2×10
m/s, find the speed of light in (a) air, (b) water.

2
3
4