Heredity and Evolution — Science STD 10 — Question

A. What is the fundamental difference between hypermetropia and myopia 3 in terms of the optical experience of a person?
B. The diagram below shows a special case of an eye defect.
(i) What is the defect that is shown in the figure?
(ii) State one cause for such a defect?
(iii) Explain with reason if a concave lens can be used to correct the defect.

Explain why, an aqueous solution of sodium chloride is not used for the electrolytic extraction of sodium metal.

An arrow 2.5cm high is placed at a distance of 25cm from a diverging mirror of focal length 20cm. Find the nature, position and size of the image formed.

A child questioned his teacher that why do organisms resemble their parents more as compared to grandparents. In which way will the teacher explain to the child?

A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggested that the genetic make up (or genotype) of the tall parent can be depicted as:

1. TTWW
2. TTww
3. TtWW
4. TtWw

Give reason for your choice.

Nervous and hormonal systems together perform the function of control and coordination in human beings. Justify this statemdent with the help of an example.

With the help of a ray diagram, state the meaning of refraction of light. State Snell’s law of refraction of light and also express it mathematically.

Some of the important fossils which have been studied are those of organisms X, Y and Z. X were marine arthropods which were common between 400 to 600 million years ago. Y were the invertebrate animals (molluscs) with a flat, coiled, spiral shell which lived in the sea about 180 million years ago. Z are the extinct carnivorous or herbivorous reptiles which appeared on the earth about 250 million years ago and became extinct about 65 million years ago. What are X, Y and Z?

Two lenses A and B have focal lengths of +20cm and, -10cm, respectively.

1. What is the nature of lens A and lens B?
2. What is the power of lens A and lens B?
3. What is the power of combination if lenses A and B are held close together?

Ten bulbs are connected in a series circuit to a power supply line. Ten identical bulbs are connected in a Parallel circuit to an identical power supply line.

1. Which circuit would have the highest voltage across each bulb?
2. In which circuit would the bulbs be brighter?
3. In which circuit, if one bulb blows out, all others will stop glowing
4. Which circuit would have less current in it?