Acids, Bases and Salts — Science STD 10 — Question

What are sexually transmitted diseases? Give two examples of sexually transmitted diseases.

What is the need of special tissues or organs for transport of substances in plants and animals?

Prepare a list of five items that you use daily in the school. Identify from the list such items that can be recycled.

Complete the following statements:
When the sun is setting, the light from it has to travel a ____ thickness of the earth's atmosphere and only ____ wavelength _____ light is able to reach us. Sunset is therefore ___.

What is tyndall effect? Explain with an example?

It is desired to obtain an erect image of an object, using concave mirror of focal length of 12cm.
Where will the image of this object be, if it is placed 24cm in front of the mirror? Draw ray diagram for this situation also to justify your answer.
Show the positions of pole, principal focus and the centre of curvature in the above ray diagrams.

Express the following facts in the form of a balanced chemical equation:“When a strip of copper metal is placed in a solution of silver nitrate, metallic silver is precipitated and a solution containing copper nitrate is formed”.

100 joules of heat is produced per second in a 4 ohm resistor. What is the potential difference across the resistor?

What is meant by bioconcentration of pesticides? Which common pesticide has accumulated in human body in considerable amounts?