Temperature and its Measurement
Question 1. The normal temperature of a healthy human being is close to ______ .
(i) 98.6 °C
(ii) 37.0 °C
(iii) 32.0 °C
(iv) 27.0 °C
Answer: (ii) 37.0 °C
Question 2. 37 °C is the same temperature as _______ .
(i) 97.4 °F
(ii) 97.6 °F
(iii) 98.4 °F
(iv) 98.6 °F
Answer: (iv) 98.6 °F
Question 3. Fill in the blanks:
(i) The hotness or coldness of a system is determined by its ________ .
(ii) The temperature of ice-cold water cannot be measured by a ________ thermometer.
(iii) The unit of temperature is degree _______ .
Answer:
(i) temperature
(ii) clinical
(iii) Celsius
Question 4. The range of a laboratory thermometer is usually .
(i) 10 °C to 100 °C
(ii) –10 °C to 110 °C
(iii) 32 °C to 45 °C
(iv) 35 °C to 42 °C
Answer: (ii) –10 °C to 110 °C
Question 5. Four students used a laboratory thermometer to measure the temperature of water as shown in Fig. 7.6:
Who do you think followed the correct way for measuring temperature?
(i) Student 1
(ii) Student 2
(iii) Student 3
(iv) Student 4
Answer: (ii) Student 2
Question 6. Colour to show the red column on the drawings of thermometers (Fig. 7.7) as per the temperatures written below:
Answer: Hint: In the first thermometer for 14 °C colour up to two small lines above mark 10 (each small line indicates 2 degrees Celsius).
In the second thermometer for 17°C colour up to seven small lines above mark 10 (each small line indicates 1 degree Celsius).
In the third thermometer colour up to fifteen small lines above mark 0 (each small line indicates 0.5 degree Celsius). Red lines are marked alongside the respective thermometers for information.
Question 7. Observe the part of thermometer shown in Fig. 7.8 and answer the following questions:
(i) What type of thermometer is it?
Answer: It is a laboratory thermometer.
(ii) What is the reading of the thermometer?
Answer: The reading of the thermometer is 26 °C.
(iii) What is the smallest value that this thermometer can measure?
Answer: There are 10 small line marks between any 10 degrees (0-10, 10-20 and so on) on the thermometer. So the thermometer can measure the smallest value of – 10°C.
Question 8. A laboratory thermometer is not used to measure our body temperature. Give a reason.
Answer: A laboratory thermometer is not used to measure body temperature because it has a larger range (-10 °C to 110 °C) and does not have a constriction that prevents mercury from falling, which is essential when measuring body temperature.
Question 9. Vaishnavi has not gone to school as she is ill. Her mother has kept a record of her body temperature for three days as shown in Table 7.4.
(i) What was Vaishnavi’s highest recorded temperature?
Answer: Vaishnavi’s highest recorded temperature was 40.0 °C.
(ii) On which day and at what time was Vaishnavi’s highest temperature recorded?
Answer: Vaishnavi’s highest temperature was recorded on Day 1 at 7 pm.
(iii) On which day did Vaishnavi’s temperature return to normal?
Answer: Vaishnavi’s temperature returned to normal on Day 3.
Question 10. If you have to measure the temperature 22.5 °C, which of the following three thermometers will you use (Fig. 7.9)? Explain.
Answer: I will use thermometer (b) because it likely has a range that includes 22.5 °C, and the divisions on the thermometer allow for precise measurements of half-degrees, such as 22.5 °C.
Question 11. The temperature shown by the thermometer in Fig. 7.10 is
(i) 28.0 °C
(ii) 27.5 °C
(iii) 26.5 °C
(iv) 25.3 °C
Answer: (ii) 27.5 °C
Question 12. A laboratory thermometer has 50 divisions between 0 °C and 100 °C. What does each division of this thermometer measure?
Answer: Each division of the thermometer measures 2 °C (100°C / 50 divisions = 2°C per division).
Question 13. Draw the scale of a thermometer in which the smallest division reads 0.5 °C. You may draw only the portion between 10 °C and 20 °C.
Answer: You would draw a scale with ten divisions between each degree, with each small division representing 0.5 °C.
Question 14. Someone tells you that she has a fever of 101 degrees. Does she mean it on the Celsius scale or Fahrenheit scale?
Answer: She means it on the Fahrenheit scale, as 101°F is a common fever temperature. On the Celsius scale, this would be about 38.3°C.
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Question. Can it always be correctly judged that a person has a fever only by touching the person?
Answer: No, it cannot always be correctly judged if a person has a fever just by touching. Our sense of touch is not a reliable method to measure temperature accurately. It is better to use a thermometer to get an accurate reading.
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Question. Do small children generally have slightly higher body temperatures as compared to adults?
Answer: Yes, small children generally have slightly higher body temperatures compared to adults. This is because their metabolic rate is higher, which can lead to slightly elevated body temperatures.
Question. Do old people, even when healthy, generally have lower body temperatures than young adults?
Answer: Yes, old people generally have lower body temperatures than young adults, even when they are healthy. Aging tends to slow down metabolism, which can result in slightly lower body temperatures.
Question. Can a clinical thermometer be used for measuring the temperature of boiling water? Or for measuring the temperature of ice?
Answer: No, a clinical thermometer cannot be used for measuring the temperature of boiling water or ice. The range of a clinical thermometer is typically from 35°C to 42°C, which is suitable for measuring body temperature but not for extreme temperatures like boiling water or ice.
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