Our Environment — Science STD 10 — Question

If the image formed by mirror for all positions of the object placed in front of it is always virtual and diminished, state the type of the mirror. Draw a ray diagram in support of your answer. Where are such mirrors commonly used and why?

What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?

Why does the rate of breathing in aquatic animals is faster than others?

How are we able to see nearby and also the distant objects clearly?

1. Draw a ray diagram to show the refraction of light through a glass slab and mark angle of refraction and the lateral shift suffered by the ray of light while passing through the slab.
2. If the refractive index of glass for light going from air to glass is 3/2, find the refractive index of air for light going from glass to air.

(i) Name a metal for each case:
(a) It does not react with cold as well as hot water but reacts with steam.
(b) It does not react with any physical state of water.
(ii) When calcium metal is added to water the gas evolved does not catch fire but the same gas evolved on adding sodium metal to water catches fire. Why is it so?

a. Draw a diagram of human excretory system and label on it the following parts:
i. Kidney
ii. Ureter
iii. Urinary bladder
iv. Urethra
b. Write one main function each of the labelled parts.

How is charcoal prepared? Explain why, charcoal is a better fuel than wood.

Explain how the sex of the child is determined at the time of conception in human beings.