Q.1. A large number of physical and chemical Ganges are taking place around us. Some of these
are natural while some others are due to human activity. Some of these cause pollution
while some others are essential for llfe.
Now, answer the following questions :
b) In early times, quick lime was used for white-wash. Now a days, use of paints has become
very common. Do you think it is better in all respects or you think it is not?
i Cooking of food is a chemical reaction. Cooking can be done using cow-dung cakes/wood or
LPG cylinder or solar cooker or microwave oven. Which one do you think is the best and
why?
(id) We should eat freshly cut apple. Why?
(iv) We tell children not to eat too many chocolates. How would you explain to them the mode by
which their teeth are damaged?
Answers
Answer:
this is so lengthy question yrr
so time waste to read and explanation sorry but I cant solve this question answer
Answer:
1.b)Quick lime is the best for white-wash as it gives proper shining though it takes some days with respect to paint.
And moreover, quiick lime is not harmful to the environment though nowadays paints are manufactured environment-friendly.
i.There are various non-renewable source of energy available like fosill fuel, coal,natural gas etc. We should avoid use of these fuels because these are limited in nature.
Cow dung cake and wood produce high amount of pollutants which is not good for environment; They also have very low calorific value. LPG gase is ideal for cooking but their availabily is also limited. Microvave cooking is not very efficient and it also produces harmful radiation.
So We should use solar cooker for cooking because it's efficient and renewable source of energy.
LPG is sevcond best option it can be used in rainy and cloudy season when solar energy is not available.
(id)We should eat freshly cut apples because apple contains iron . If a cut apple is kept for a few minutes then the iron in it starts to rust, causing the apple to turn brown .
(iv)Cavities refer to tooth decay, which occurs when specific types of bacteria produce acid that destroys the tooth’s enamel and its underlying layer, the dentin.
Tooth decay is one of the most common causes of tooth pain. Tooth decay begins when the enamel begins to break down, creating pockets of decay on the surface of the teeth. Decay results from acidic damage to the tooth structure produced by bacteria that lives in plaque, the sticky film formed by the protein found in one’s saliva metabolizing sugary foods left in the mouth.
When we eat and drink, these bacteria create acids, which can dissolve the protective layer beneath the retained plaque. The acid removes minerals from the enamel, which if left untreated can cause a cavity. Decay begins in the main portion of the tooth (the enamel) and as the enamel is broken down the decay can go deeper into the dentin and can eventually reach the nerve (pulp) of the tooth.