Recent questions tagged heat-energy

Description : Describe a simple experiment to study the thermal expansion of Gases.

Last Answer : I. Take an empty flask and fit a cork into the mouth of the flask. II. Limb of the U shaped glass tube through the cork. III. Clamp the flask in a stand as shown in fig. IV. Dip the ... and produce bubbles in water. X. On cooling flask contracts and water level is pulled up in the glass tube.

Description : Explain the expansion of liquids and with the help of an experiment.

Last Answer : I. Take an empty flask and fit a cork into its mouth. Pass short limb of U-shape glass tube through it. II. Clamp the flask in a stand. III. Dip the long limb of U-shaped tube in the water ... . On cooling, air in the flask contracts, so suction is created which pulls the water in the glass tube up.

Description : Describe the effects of expansion and contraction of solids.

Last Answer : I. In hot summer, concrete in roads expands and road surface crack. II. Two sections of railway track are laid with gaps. If there are no gaps, then they may be de-shaped due to expansion ... gap is also present at this end. So that it can move forward and backward during expansion and contraction.

Description : Explain the damages which are caused by expansion or contraction by giving two examples.

Last Answer : I. In hot summer, the concrete used in roads expands. If no space is provided for its expansion, then road surface crack. II. Two sections of railway track are laid with gaps. If there are no gaps, then they may be de-shaped due to expansion in summer.

Description : What is thermometer? How it works?

Last Answer : A thermometer is a device used to measure the temperature. When some hot object touch the bulb of the thermometer, the liquid inside the narrow tube expands and rises up and we can measure the temperature by reading scale.

Description : Explain the peculiar (strange) behavior of water during contraction and expansion.

Last Answer : On heating the liquid water from 0 0C to 4 0C, it contracts and its volume decreases while its density increases. On cooling from 4 0C to 0 0C it expands, its volume increases and density decreases.

Description : Demonstrate how a bimetallic strip works in a thermostat.

Last Answer : In electric iron, when current passes through heating element, it becomes hot. The connected bimetallic strip also heats up. On getting hot, it bends and is disconnected from heating element so, circuit breaks and switches off the electric iron.

Description : What is Rivet and Riveting?

Last Answer : A rivet is a small, cylindrical and smooth shaft whose one end is swollen (called Head) while the other end is flat. Hot rivets are used to join the metal plates. The process in which two metal plates are joined together by means of rivets is called riveting.

Description : What is thermal expansion? Explain it with the help of experiment.

Last Answer : The expansion of material objects on heating is called thermal expansion. I. Take a metallic sphere which can pass easily through a ring. II. Remove the sphere out of the ring. III. Now heat the ... expansion due to heating. V. On cooling the sphere, it attracts and passes through the ring again.

Description : When a vessel containing a liquid is heated, the level of liquid initially falls and then rises up. Why does it happen so? OR Describe the irregular expansion of liquid.

Last Answer : On heating the liquid water from 0 degree C to 4 degree C, it contracts so the level of liquid initially falls. But after 4 degree C it expands so liquid rises up.

Description : Why do gases expand faster than liquids and solids?

Last Answer : Because the particles of gases are widely disturbed i.e. their particles are far apart from each other and they free to move. Other

Description : Why do hot air balloons rise up?

Last Answer : Since hot gases rose up in air, so hot air in balloon causes it to rise up.

Description : Why gaps are left between two sections of a railway track?

Last Answer : The gaps allow the expansion and contraction of rails during summer and winter season.

Description : Why one end of the iron girders is placed on rollers in construction of bridges?

Last Answer : One end of iron girders is placed on the rollers along with a gap at this end so that girder can move forward and backward during expansion or contraction.

Description : Why is water not used instead of mercury in thermometers?

Last Answer : Because Mercury has high coefficient of expansion per unit rise in temperature

Description : Write down the effects of heating and cooling on gases

Last Answer : Gas expand on heating and contract on cooling

Description : Write down the effects of heating and cooling on solids

Last Answer : Solid expand on heating and contract on cooling