Heredity and Evolution — Science STD 10 — Question

How do Menders experiment show that traits are inherited independently?

Calculate the image distance for an object of height 12mm at a distance of 0.20m from a concave lens of focal length 0.30 m, and state the nature and size of the image.

Describe the process of respiration in State whether it is anaerobic respiration or aerobic respiration.

A food chain consists of fish, larvae, phytoplanktons and birds. The level of pesticides in water in which the fish, larvae and phytoplanktons live is quite high.

1. In which organisms the pesticides enter from the polluted water? What is this level of organisms known as?
2. Which organism will have the maximum amount of pesticides accumulated through the food chain? What is this process known as?
3. Write the food chain comprising all the organisms mentioned above.
4. Which other organism you could write in place of bird in the above food chain?

In the nuclear reactor of a power plant:

1. How do control rods control the rate of fission?
2. How is heat removed from the reactor core, and what use is made of this heat?

A compound X which is prepared from gypsum has the property of hardening when mixed with a proper quantity of water.

1. Identify the compound X,
2. Write the chemical equation for its preparation.
3. For what purpose is it used in hospitals?

Give reason for the following:

1. Which has low melting point.
2. Which exist in liquid state at room temperature.
3. Which is most abundant in earth's crust.
4. Which is placed at the top of the reactivity series.

A silver article generally turns black when kept in the open for a few days. The article when rubbed with toothpaste again starts shining.

1. Why do silver articles turn black when kept in the open for a few days? Name the phenomenon involved.
2. Name the black substance formed and give its chemical formula.

When an object is placed 10cm in front of lens A, the image is real, inverted, magnified and formed at a great distance. When the same object is placed 10cm in front of lens B, the image formed is real, inverted and same size as the object:

1. What is the focal length of lens A?
2. What is the focal length of lens B?
3. What is the nature of lens A?
4. What is the nature of lens B?