Physics - Study Mode
[#226] Pipelines in cold countries often burst in winter, because
Correct Answer
(A) Water freezes and expands in its volume
Explanation
Solution: Water in pipes freeze in cold countries. Due to the anomalous expansion of water, it expands instead of contacting when there is a fall in temperature below 4°c. So, the water pipes burst due to the excess space consumed by the ice after freezing.
[#227] In severe winter, in cold countries water pipes burst because
Correct Answer
(A) Water expands on freezing
Explanation
Solution: Water in pipes freeze in cold countries. Due to the anomalous expansion of water, it expands instead of contacting when there is a fall in temperature below 4°c. So, the water pipes burst due to the excess space consumed by the ice after freezing.
[#228] Railway tracks are banked on curves so that
Correct Answer
(C) Necessary centripetal force may be obtained from the horizontal component of the weight of the train
Explanation
Solution: Railway tracks are banked at the curves so that the necessary centripetal force may be obtained from the horizontal component of the reaction on the train.
[#229] The density of the liquid when heated
Correct Answer
(A) Decreases
Explanation
Solution: When a liquid is heated, its volume increases and mass of liquid being same density decreases.
[#230] Thermocouple consists of
Correct Answer
(A) Two dissimilar metals
Explanation
Solution: A thermocouple consists of two dissimilar metals, joined together at one end. When the junction of the two metals is cooled or heated a voltage is produced that can be correlated back to the temperature. Most thermocouple alloys are commonly available as wire.