Sources of Energy — Science STD 10 — Question

Where are such sacred groves in Maharashtra? Make a list and visit with your teachers.

 How can the rate of the chemical reaction, namely, decomposition of hydrogen peroxide be increased?

The p.d. across a lamp is 12V. How many joules of electrical energy are changed into heat and light when:

1. A charge of 1C passes through it?
2. A charge of 5C passes through it?
3. A current of 2A flows through it for 10s?

Write down the names of international organizations that work for disaster management.

A food chain occurring in the sea which provides food for many people can be written as:
phytoplankton → zooplankton → X → Y

1. Name one phytoplankton.
2. Name two zooplanktons.
3. What could be X?
4. Name the organism which Y could be.
5. Which organism in the above food chain is a (i) primary consumer, and (ii) tertiary consumer?

With the help of a labelled ray-diagram, describe how a plane mirror forms an image of a point source of light placed in front of it. State the characteristics of the image formed in a plane mirror.

The organ A which is located inside the skull of our body is protected by a bony shell B. It is surrounded by three layers membranes C. The spaces between these layers are filled with a liquid D which protects organ A from mechanical shocks. Organ A in combination with another organ E makes up the central nervous system.

1. What is organ A?
2. What are B, C and D?
3. Name the organ E.
4. While walking barefoot, if we happen to step on a sharp piece of stone, we immediately lift our foot up. Which of the two organs: A or E, is directly involved in this action?
5. If we step out from a darkened room into bright sunlight, we close our eyes for a moment. Which of the two organs: A or E, is directly involved in this action?

With a neat labelled diagram, describe the experiment to demonstrate dispersion of sunlight (white light) by a prism.

what basis and how will you determine whether air is saturated with vapour or not?

The gland X which is located just below the brain in the human head secretes a chemical substance Y which controls the development of ones and muscles in the body of a person. Secretion of too little of substance Y as well as the secretion of too much of substance Y by the gland X leads to abnormal development of the body of a person.

1. Name the gland X.
2. What is the chemical substance Y?
3. What happens if too little of substance Y is secreted?
4. What happens if too much of substance Y is secreted?
5. Name the system of glands in the human body of which gland X is a part.