Give reasons for the following:
(a) Iron rims are heated red hot before 'fixing them on cart wheels.
(c) A new quilt is warmer than an old one.
(d) A brass tumbler feels much cooler than a wooden tray on a chilly day
(e) The bottoms of cooking utensils are often kept black.
(b) A clinical thermometer has a slight bend, or kink, in its capillary tube................. please give correct answer
Answers
Answer:
a) Iron rims are made slightly smaller than the wheels. They are heated red hot before fixing them on the cart wheels to expand them so that they can be easily fixed on the wheels and water is poured on them to cool them. As the rims cool they contract and take the shape of the wheel and get firmly fixed on the wheels.
c) Iron rims are made slightly smaller than the wheels. They are heated red hot before fixing them on the cart wheels to expand them so that they can be easily fixed on the wheels and water is poured on them to cool them. As the rims cool they contract and take the shape of the wheel and get firmly fixed on the wheels.
d) Brass is a good conductor of heat. Therefore when one touches the brass tumbler, heat is conducted from the body to the tumbler easily. So the temperature of the body reduces the and the brass tumbler feels much cooler than a wooden tray.
e) Cooking Utensils are painted black from bottom to absorb more heat and get heated quickly. Cooking Utensils are highly polished from inside to reduce loss of heat and keep warm for a longer time.
b) A clinical thermometer has a narrow kink in the capillary tube because when Mercury expands, it pushes through the kink, but when it's taken out of patient mouth, Mercury does not go back to the bulb beacuse if it. Hence, doctor can read the patients temperature easily .