P-1 Lenses — Science STD 10 — Question

The power of a lens with focal length 20 cm is………..

State three reasons (of which at least one must be chemical) for believing that sodium is a metal.

What name has been given to those organisms which break down the complex organic compounds present in dead animals and plants?

 The change in…………of light rays while going from one medium to another is called refraction.

Give the common name and IUPAC name of the simplest aldehyde.

Name two animals which undergo external fertilisation and two animals which undergo internal fertilisation?

In a human, how many chromosmes are present in:an egg which has just been produced by the ovary?

Why do some people need to use a dialysis machine? What does the machine do?

What type of chemical bonds are present in a solid compound which has a high melting point, does not conduct electricity in the solid state but becomes a good conductor in the molten state?

How does Amoeba engulf the food particle?