Light – Reflection and Refraction — Science STD 10 — Question

i. Compare soaps and detergents on the basis of their composition and cleansing action in hard water.
ii. What happens when ethanol is treated with sodium metal? State the behaviour of ethanol in this reaction.
iii. Draw the structure of cyclohexane.
iv. Name the following compound.

List the factors on which diffusion in the plants depends.

Give one example to show how the participation of local people can lead to the efficient management of forests.

A worm X found in freshwater and slow-moving streams has been accidently cut into three pieces. It was observed that in due course of time, each cut piece of the worm develops to become a complete worm by growing all the missing parts.

1. Name the worm X which can exhibit this phenomenon of making complete worm from its cut body parts.
2. Name another organism Y which possesses the same characteristic of growing fully from its cut body parts.
3. What is the name of this process in which a complete organism is formed from its cut body part.
4. State whether X and Y are unicellular and/or multicellular organisms.
5. Can a dog be produced completely form its cut body part (say, a cut tail) just like organisms X and Y? Why?

What are the possible blood groups likely to be inherited by children born to a group A mother and a group B father? Explain your reasoning.

Properties of the elements are given below. Where would you locate the following elements in the periodic table?

1. A soft metal stored under kerosene.
2. An element with variable (more than one) valency stored under water.
3. An element which is tetravalent and forms the basis of organic chemistry.
4. An element which is an inert gas with atomic number 2.
5. An element whose thin oxide layer is used to make other elements corrosion resistant by the process of “anodising”.

'Nervous and hormonal systems together perform the function of control and coordination in human beings.' Justify the statement.

Redraw the circuit of Question 1, putting in an ammeter to measure the current through the resistors and a voltmeter to measure the potential difference across the 12 Ω resistor. What would be the readings in the ammeter and the voltmeter?

How are fats digested in our bodies? Where does this process take place?

Why is variation during reproduction beneficial to the species but not necessarily for the individual?