Metals and Non-Metals — Science STD 10 — Question

What is the difference between the food habits of organisms belonging to the first and the third trophic levels? Give one example each of the organisms belonging to these two trophic levels.

What is photosynthesis?

Write down the magnification formula for a lens in terms of object distance and image distance. How does this magnification formula for a lens differ from the corresponding formula for a mirror?

Write two differences between binary fission and multiple fission in a tabular form.

What is overloading of an electric circuit?

“Fossil fuels are known as conventional source of energy.” Give reason.

What is puberty? Who attains puberty at an earlier age in human beings: male or female (boy or girl)?

When a person breathes in air, the air enters into his body through an organ Ahaving two holes B in it. The air then passes through pharynx and larynx and enters into a tube C. The tube C divides into two smaller tubes D at its lower end. The two smaller tubes are attached to two respiratory organs E. Each smaller tube divides inside the organs E to form a large number of still smaller tubes called F. The smallest tubes F have air-sacs G at their ends in which gaseous exchange takes place in the body of the person. What are A, B, C, D, E, F and G?

A metal M does not liberate hydrogen from acids but reacts with oxygen to give a black colour product. Identify M and black coloured product and also explain the reaction of M with oxygen.