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Sunny Mathew

Feb 4, 2015

#### HOW DOES THERMOS FLASK MINIMISE HEAT TRANSFER BETWEEN THE CONTENTS OF THE BOTTLE AND OUTSIDE?



The thermos flask consists of a double-walled glass vessel resting on a cork inside a metal or plastic case. The outer surface of its inner wall and the inner surface of its outer...

Sangeeta Gupta

Dec 8, 2014

#### Explain  water equivalent in simple words with examples.



Water equivalent of a substance is the amount of water that would absorb the same amount of heat as the substance per degree rise in temperature.

Expl...

Sagar Rachchh

Dec 21, 2014

#### What is  difference  between  SI  units  and  CGS  units. Why  do we  study both  of  these?



In CGS system the unit of length, mass and time are centimetre (cm), gram (g) and second (s), respectively.

In SI system the unit of length, mass and time are metre (m), kilogram (kg) and second (s),...

Sarita jain

Dec 5, 2014

#### A cubical block is floating inside a tub containing a liquid. The temperature of the system is increased by a small temperature Î”T. It was found that the depth of the submerged portion of the block does not change. Find the relation between the coeffecient of linear expansion (Î±) of the block and volume expansion (É£) of the liquid.



This answer is wrong since É£=3Î± has to be proved so we can't use this...using the information given in this question

Sangeeta Gupta

Dec 9, 2014

#### Thermal conductivity (k) of a substance depends or does not depend on area of cross section of materials?



Thermal conductivity of a material is independent of area of cross section of the material. It depends only on the nature of the material.

The coefficient of thermal conductivity (k) of a materia...

Rajat Pandey

Dec 26, 2014

#### When a block of iron floats in mercury at 0Â°C, a fraction k1 of its volume is submerged while at the temperature 60Â°C, a fraction k2 is seen to be submerged. If the coeffecient of volume expansion of iron is É£(fe)and that of mercury is É£(Hg), find the ratio k1/k2.



Let V0 and V be the volumes of the iron block at T = 0 Â°C and 60 Â°C, respectively. Then we can write

V = V0 + V0TÉ£Fe = V0 (1 ...

Misha Jain

Jun 8, 2014

#### A uniform thermometer scale is at steady state with it's 0 cm mark at 20 degrees Celsius and 100 cm mark at 100 degrees Celsius. Temperature of the 60 cm mark is



100 cm corresponds to 80Â°C
1 cm corresponds to 80Â°C/100 cm = 0.8Â°C
So 60 cm corresponds to 60 x

Sangeeta Gupta

Dec 9, 2014

#### When air is a bad conductor of heat then how does the air above land during day gets heated up?



Air, being a poor conductor of heat, becomes warmer by absorption of heat radiated from the sun.  The transfer of heat in air takes place by convection. Warm air being less dense goes up and cold air being...

Angana borah

Jan 6, 2015

#### Why for gases coefficient of volume expansion is dependent on temperature while for liquids it is not?



The coefficient of volume expansion is given by Î±v = (Î”V/V)(1/Î”T).
The extent to which solids and liquids expand, in general, depends on their dimensions and the temperature...

Feb 1, 2015

#### Why there is a gap between railway lines?



The railway lines are metals. They become longer in summer. For this reason the lines become bent and there exists a lot of possibility of accidents of trains. So there is a gap between railway lines.

Sunny Mathew

Feb 4, 2015

#### HOW DOES THERMOS FLASK MINIMISE HEAT TRANSFER BETWEEN THE CONTENTS OF THE BOTTLE AND OUTSIDE?



The thermos flask consists of a double-walled glass vessel resting on a cork inside a metal or plastic case. The outer surface of its inner wall and the inner surface of its outer...

Sangeeta Gupta

Dec 8, 2014

#### Explain  water equivalent in simple words with examples.



Water equivalent of a substance is the amount of water that would absorb the same amount of heat as the substance per degree rise in temperature.

Expl...

Sagar Rachchh

Dec 21, 2014

#### What is  difference  between  SI  units  and  CGS  units. Why  do we  study both  of  these?



In CGS system the unit of length, mass and time are centimetre (cm), gram (g) and second (s), respectively.

In SI system the unit of length, mass and time are metre (m), kilogram (kg) and second (s),...

Sarita jain

Dec 5, 2014

#### A cubical block is floating inside a tub containing a liquid. The temperature of the system is increased by a small temperature Î”T. It was found that the depth of the submerged portion of the block does not change. Find the relation between the coeffecient of linear expansion (Î±) of the block and volume expansion (É£) of the liquid.



This answer is wrong since É£=3Î± has to be proved so we can't use this...using the information given in this question

Sangeeta Gupta

Dec 9, 2014

#### Thermal conductivity (k) of a substance depends or does not depend on area of cross section of materials?



Thermal conductivity of a material is independent of area of cross section of the material. It depends only on the nature of the material.

The coefficient of thermal conductivity (k) of a materia...

Rajat Pandey

Dec 26, 2014

#### When a block of iron floats in mercury at 0Â°C, a fraction k1 of its volume is submerged while at the temperature 60Â°C, a fraction k2 is seen to be submerged. If the coeffecient of volume expansion of iron is É£(fe)and that of mercury is É£(Hg), find the ratio k1/k2.



Let V0 and V be the volumes of the iron block at T = 0 Â°C and 60 Â°C, respectively. Then we can write

V = V0 + V0TÉ£Fe = V0 (1 ...

Misha Jain

Jun 8, 2014

#### A uniform thermometer scale is at steady state with it's 0 cm mark at 20 degrees Celsius and 100 cm mark at 100 degrees Celsius. Temperature of the 60 cm mark is



100 cm corresponds to 80Â°C
1 cm corresponds to 80Â°C/100 cm = 0.8Â°C
So 60 cm corresponds to 60 x

Sangeeta Gupta

Dec 9, 2014

#### When air is a bad conductor of heat then how does the air above land during day gets heated up?



Air, being a poor conductor of heat, becomes warmer by absorption of heat radiated from the sun.  The transfer of heat in air takes place by convection. Warm air being less dense goes up and cold air being...

Angana borah

Jan 6, 2015

#### Why for gases coefficient of volume expansion is dependent on temperature while for liquids it is not?



The coefficient of volume expansion is given by Î±v = (Î”V/V)(1/Î”T).
The extent to which solids and liquids expand, in general, depends on their dimensions and the temperature...