Question

4 ml
2 mily
(a) What can you conclude about spread of the disease with respect to the distance from an infected
person?
(b) What change will be observed in the above situation if the infected person is present in a closed
room?
(c) Name two diseases that can be spread through the above means.
(d) How can the spread of such diseases be controlled ?
OR
Justify the following statements :
(a) "Availability of proper and sufficient food would prevent from infectious diseases".
(b) "The general ways of preventing infection mostly relate to preventing exposure".
List three points of prevention of exposure.
35. (i) Can a homogeneous mixture have a variable composition ? Justify giving an example.
(ii) What happens when :
(a) Dilute sulphuric acid is added to a mixture of iron filings and sulphur powder.
(b) Dilute sulphuric acid is added to a mixture of iron filings and sulphur powder heated to red
hot followed by cooling.
36. (i) To estimate the height of a bridge over a river, a stone is dropped freely in the river from the
bridge. The stone takes 2 s to touch the water surface in the river. Calculate the height of the bridge
from the water level.
(ii) Suppose a planet exists whose mass and radius both are half those of earth. Calculate th
acceleration due to gravity on the surface of this planet.​

Answer 1

Answer:

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