Chapter 4 Thermometry Long Answer Type Questions
Question 1. If a person enters a room at 25 °C, will thermal equilibrium be established?
Answer:
A person enters a room at 25 °C:
Normal body temperature of a human being is 37 °C. The human body maintains this temperature, generating energy through food intake. Hence, thermal equilibrium will not be established unless the temperature of the room rises to 37 °C due to some external reasons.
Question 2. In inter blankets and quilts warm up after being wrapped around a body. Why?
Answer:
In inter blankets and quilts warm up after being wrapped around a body
The normal temperature of the body is 37 °C. Blankets, quilts etc. are at a lower temperature in winter. After being wrapped, they warm up by taking heat from the body, and after some time thermal equilibrium is established. This means that their temperature also increases to 37 °C.
Question 3. When would two chairs, one made of wood and the other of iron, feel equally hot or cold?
Answer:
When the temperature of the chairs are equal to our body temperature, thermal equilibrium will exist between the body and the two chairs, preventing any heat flow. Then they will appear equally hot or cold on touch.
Question 4. How can a thermometer be used to find out whether the atmospheric pressure is above or below its normal value?
Answer:
Pure water boils at 100 °C when its superincumbent pressure is equal to the normal atmospheric pressure. With the decrease or increase in the superincumbent pressure, its boiling point decreases or increases.
A thermometer determines the boiling point. Boiling point, higher or lower than 100 °C, indicates atmospheric pressure as above or below the normal value (water surface should be open to the atmosphere).
Question 5. Is there any thermal equilibrium in the solar system?
Answer:
As the temperatures of the sun, the planets and their satellites are not the same, there is no thermal equilibrium in the solar system.
Question 6. What happens when water at 80 °C is mixed with water at 20 °C?
Answer:
Heat will be transferred from water at 80 °C to that at 20 °C till thermal equilibrium is achieved. Then both samples would attain an equal temperature somewhere between 20 °C and 80 °C.
Question 7. There are two thermometers in a room. One reads the temperature as 25 degrees and the other as 77 degree. Why is a difference?
Answer:
There are two thermometers in a room. One reads the temperature as 25 degrees and the other as 77 degree
The two thermometers must be measuring the temperatures on two different scales.
As 25 °C = 77 °F, the reading of 25 degree should be in a Celsius thermometer and 77 degrees in a Fahrenheit thermometer.
Chapter 4 Thermometry Very Short Answer Type Questions
Question 1. What is the value of -273°C in Kelvin scale?
Answer: [0 K]
Question 2. What is the value of absolute zero temperature on Fahrenheit scale?
Answer: – 459.4 ° F
Question 3. Write down the physical property of a substance that is defined from the zeroth law of thermodynamics.
Answer: Temperature
Question 4. If two bodies are in thermal equilibrium, then their temperature must be equal’. State whether the statement is true or false.
Answer: True
Question 5. What is the name of the temperature-measuring instrument?
Answer: Thermometer
Question 6. Due to temperature difference only, the energy transferred from one body to another is called _______
Answer: Heat
Chapter 4 Thermometry Assertion Reason Type Question And Answers
Direction: These questions have statement 1 and statement 2 of the four choices given below, choose the one that best describes the two statements.
- Statement 1 is true, statement 2 is true; statement 2 is a correct explanation for statement 1.
- Statement 1 is true, and statement 2 is true; statement 2 is not a correct explanation for statement 1.
- Statement 1 is true, statement n is false.
- Statement 1 is false, and statement 2 is true.
Question 1.
Statement 1: Fahrenheit is the smallest unit of measuring temperature.
Statement 2: Fahrenheit was the first temperature scale used for measuring temperature.
Answer: 3. Statement 1 is true, statement 2 is false.
Question 2.
Statement 1: The temperature at which Centigrade and Fahrenheit thermometers read the same is -40°.
Statement 2: There is no relation between Fahrenheit and Centigrade temperature.
Answer: 3. Statement 1 is true, statement 2 is false.
Question 3.
Statement 1: Degree Fahrenheit is the smallest unit for measuring temperature.
Statement 2: Fahrenheit was the first temperature scale used for measuring temperature.
Answer: 3. Statement 1 is true, statement 2 is false
Question 4.
Statement 1: Two bodies at different temperatures, if brought in contact do not necessary settle to the mean temperature.
Statement 2: The two bodies may have different thermal capacities.
Answer: 1. Statement 1 is true, statement 2 is true; statement n is a correct explanation for statement 1.
Question 5.
Statement 1: Water is considered unsuitable for use in thermometers.
Statement 2: This is due to small specific heat and high thermal conductivity.
Answer: 3. Statement 1 is true, statement 2 is false
