LEVEL 2
Q1. Why are bottom of cooking utensils blackened?
Q2. Paper and dry cotton cloth catch fire easily. Why are they not used as fuels?
Q3. Mayank accidently broke the clinical thermometer while giving jreks. What do you think he should do
collect the spilled mercury?
Q 4. Why is the stem of thermometer made up of glass?
Q 5. Expansion on heating can be nuisance. Comment.
Answers
ANSWER 1:
Explanation:
Because it got oxidised and the utensils like Aluminium can be oxidised only one time ANSWER 2: Because it can not produce heat in sufficient amount
Explanation:
ans1
because dark colour absorbs more heat
ans2
because fuel is a substance which produces heat and light on a reasonable cost and have high calorific value
ans3
no because mercury is poisonous
ans 4
The stem of the thermometre made up of thick glass because of following reasons given as 1 To contain the mercury. 2 For holding mercury which is poisonous as well as to give a magnifying effect while reading
ans5
Due to high temperature in hot summer , the railway rails may expand and change. This may cause derailment of trains which travel on the track