During Diwali festival, Rajender brought a new microwave oven in his house and told his wife Sarika to use the same carefully. He also told her that microwave oven is to used for slow heating of the vegetables and food articles upto moderate temperature as that will preserve the from the food. Further, the vegetables or flood items to be heated in oven are to be kept in a porecelain vessel and not in a matallic vessel. Read the above paragraph and answer and following questions:
(i) What is the basic principle of working of microwave oven?
(ii) Why is it advised to use porcelain vessel for heating the food items in microwave oven?
(iii) What basic values do you learn from his study?

Explanation

(i) The basic principle of working of microwave oven is to create microwave radiations of siutable frequency
in the working space of oven, which may match the resonant frequency fall on food items containing
water molecules (like, fruits, vegetables,cereals etc.) placed in oven, the water molecules absorb these
radiations. As a result of it, the energy of water molecules increases. These molecules share their energy
with neighbouring molecules. Due to it, the entire gets heated.
(ii) In microwave oven, a porcelain container is used for heating the food articles in the oven. It is so becuase
the size of the molecules of porcelain container is large and they vibrate and rotate with much smaller
frequency than that of microwave and hence can not absorb microwaves. Due to it, the porcelain container
remains at relatively lower temperature.
(iii) We find that in a microwave oven, the slow and low heating of food will preserve the food values but fast
and intense heating will destroy the food values. The same is true in day to day life. Sudden rises may be
harmful. Instead, steady rises are appricable.