Carbon and its Compounds — Science STD 10 — Question

A ray of light passes from air into a block of glass. Does it bend towards the normal or away from it?

What iron compound is present in haematite ore? Also write its chemical formula.

Define trophic level. Draw the food chain with four trophic levels.

Give one example of a hydrocarbon, other than pentane, having more than three isomers.

Name the plant hormones responsible for the following:
Falling of senescent leaves.

What is the process of obtaining food by Amoeba called? What does it mean?

What is the frequency of menstrua] cycle in human females (or women)?

Two non-metals combine with by the sharing of electrons to form a compound X.
State whether X will have a high melting point or low melting point.

Name a structure associated with nervous system which is integrated with endocrine system and also secretes hormones.