P-2 Animal Classification — Science STD 10 — Question

What is radioactive pollution? What are its effects?

Give one example each of a chemical reaction characterised by:

1. Evolution of a gas.
2. Change in colour.
3. Formation of a precipitate.
4. Change in temperature.
5. Change in state.

Describe the exchange of gases which takes place in the leaves of a plant:

1. During daytime.
2. At night.

The flask-shaped organ A at the centre of a flower is surrounded by a number of little stalks B having swollen tops which lie just inside the ring of petals.

1. Name A. What are the various parts of A?
2. Which part of A contains gametes?
3. Name B. What is the swollen top of B known as?
4. What does the swollen top of b contain?
5. Out of A and B, which one is (i) male part, and (ii) female part of the flower?

Write short note: Production of Yoghurt.

A camera fitted with a lens of focal length 50mm is being used to photograph a flower that is 5cm in diameter. The flower is placed 20cm in front of the camera lens.

1. At what distance from the film should the lens be adjusted to obtain a sharp image of the flower?
2. What would be the diameter of the image of the flower on the film?
3. What is the nature of camera lens?

What is meant by the apparent size of an object? With a neat and labelled diagram, explain the relation between the apparent size of an object and the angle subtended by the object at the eye.

Describe the human male reproductive system with the help of a neat labelled diagram.

Draw a labelled diagram of the human female reproductive system. With the help of this diagram, explain the working of human female reproductive system.