Heat and Temperature: Concepts and Applications

It is incorrect to say that heat cannot be transformed in other forms of energy. Heat energy is converted into mechanical energy. For example, a steam engine pulls a train.  

Energy is defined as the capacity to do work. The S.I unit of energy is Joule. When energy is transferred from one object to another due to temperature difference, it is called heat.

Stars are luminous objects. They have their own light. All the stars, like Sun, consist of hydrogen atoms which fuse together to emit heat and light, which fall on the earth. 

James watt framed the idea that heat energy can be transformed into other forms of energy. The heat energy can also be generated from other various form of energy. Keeping these ideas in his mind, he used the chemical energy of fuel, like coal, to produce steam to rotate the shaft of the engine. In other words, we can say that the heat energy is converted into mechanical energy.

In geyser, electrical energy is converted into heat energy. This option is incorrectly matched. 

Calorimeter is an instrument, used to measure the heat evolved in a process. The principle behind this instrument is, Heat lost = Heat gained. 

The degree of hotness of a body is known as its temperature. 

Heat can kill the harmful bacteria and germs. This property of heat helps in keeping the food items, preserved for a longer time. This is why, food is heated to increase its shelf life.

Fahrenheit scale thermometer is used by the doctors to measure the temperature of a patient. 

Shape of the object has nothing to do with the selection of a thermometer to be used in measuring the temperature.

Kelvin is the S.I unit of measuring temperature. 

It is the temperature of a normal healthy human body on Fahrenheit scale. 

It is the boiling point of water on Kelvin scale. 

It is not correct because its expansion is uniform over a wide range of temperature. This property of mercury helps in giving the reliable measure of temperature. 

Photosynthesis is the process by which green plants prepare their own food. In this process, heat energy is trapped by chlorophyll for the conversion of raw material into carbohydrate.

The kink is a bend in the capillary tube of a clinical thermometer. It prevents the mercury from falling back after the thermometer is removed from the patient's mouth. 

As we know that a substance contracts on cooling. So, the telephone wires between two poles are kept loose to allow their contraction during winter.

The temperature in Celsius scale is converted into Fahrenheit temperature by using the following formula:
 The Fahrenheit temperature; ⁰F = ( ⁰C  X 1.8 ) + 32,  ⁰F = ( 37⁰C  X 1.8 ) + 32, ⁰F = ( 66.6 + 32 ) =98.6⁰F . 

The degree of hotness of a body is called its temperature. The direction of flow of heat energy is always from a body at higher temperature to a body at lower temperature. 

The temperature in Kelvin scale is converted into Fahrenheit temperature by using this formula.  
 ⁰F     =    (K - 273.15) X 9/5 + 32          
 ⁰F = (350  - 273.15) X 9/5 + 32 
⁰F = (76.85 X9/5 +32) =170.33⁰F 

While drilling the hole, mechanical energy of drill gets converted into heat and sound energy. The heat energy makes the drill hot.  

Calorie is known as the common unit of heat. It is that amount of heat which can raise the temperature of 1 gram of water by 1⁰C. One calorie = 4.2 Joules. 

We know that 4.2 Joules of heat energy is required to raise the temperature of 1 gram of water by 1⁰C. So, heat energy required to raise the temperature of 100 grams of water by 3⁰C is 1260 Joules (100 X4.2 X3 = 1260)

On both the scales, the number of divisions are 100 and each calibrated line differs by 1⁰.

The clinical thermometer is dipped in an antiseptic solution prior to use to keep a patient safe from further infection. It is frequently used by the patients suffering from different diseases.