Pressure cooker

Ans. 

(i) In ordinary vessel, both heat and steam produced during cooking escape from the vessel resulting into more consumption of energy and leads to wastage of time to cook. 

(ii) But in pressure cooker the both the heat and steam is trapped due to the structure of cooker and its tight lid. 

(iii) Because of this there is an increase in vapour pressure and produces more heat. 

(iv) This steam and heat help to cook faster and save fuel at the same time.