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प्रश्न
Why are bridges made of steel girders put on rollers?
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उत्तर
The beams of the bridges expand maximum during the summer days and contract maximum during the winter nights. If the beams are fixed at both ends on the pillars, they may develop crack due to expansion and contraction. To avoid this, beams are made to rest on rollers on the pillars to provide space for expansion.
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संबंधित प्रश्न
Fill in the blank
The S.I. unit of temperature is ________.
Two bodies at different temperatures are placed in contact. State the direction in which the heat will flow.
Express Kelvin Zero in °C
What is the relation between joule and calorie?
Do all substances expand on heating? Give examples.
The hot metal ball is suspended from a string in a metal box as shown in the following figure
(i) What are the ways in which the ball loses heat
(ii) Which side of the box will be the hottest and which the least hot after some time? Explain.
Where am I?
The isotherm 0°C runs in my surroundings.
Who am I?
I connect places of equal temperature.
Match the following
| 1. | Heat | 0o C |
| 2. | Temperature | 100o C |
| 3. | Thermal Equilibrium | kelvin |
| 4. | Ice cube | No heat flow |
| 5. | Boiling water | joule |
