P-2 Environmental management — Science STD 10 — Question

Does geographical isolation of individuals of a species lead to the formation of a new species? Provide a suitable explanation for your answer.

A plant has two varieties, one with red petals and the other with white petals. When these two varieties are cross-pollinated, all the offsprings have red petals?

1. Which gene is dominant?
2. Choose suitable letters to represent the two genes.

DEFINE : Hydro-electric power plant:

Explain the term free fall and state the corresponding kinematical equations of motion in the usual

Light travels more quickly through water than through glass:

1. Which is optically denser: Water or glass?
2. If a ray of light passes from glass into water, which way will it bend: Towards the normal or away from the normal?

Lithium, sodium and potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements? Explain your answer.

Identify the type of disaster: Soil erosion.

Study the following procedure and answer the questions below: (Practice Activity Sheet – 2)
1. Take 3 spheres of iron, copper and lead of equal mass.
2. Put all the 3 spheres in boiling water in a beaker for some time.
3. Take 3 spheres out of the water. Put them immediately on a thick slab of wax.
4. Note the depth that each sphere goes into the wax.
(i) Which property of a substance can be studied with this procedure?
(ii) Describe that property in minimum words.
(iii) Explain the rule of heat exchange with this property.

If the number of carbon atoms in the molecular formulae of alkenes is denoted by ‘n’ what will be the number of hydrogen atoms?