Heat And Temperature Book Back Questions 7th Science Lesson 8

7th Science Lesson 8

8] Heat And Temperature

Book Back Questions with Answer and Do You Know Box Content

Do You Know?

In humans, the average internal temperature is 37^oC (98.6^oF), though it varies among individuals. However, no person always has exactly the same temperature at every moment of the day. Temperatures cycle regularly up and down through the day according to activities and external factors.

Maximum – minimum thermometer: The maximum and minimum temperatures of the previous day reported in weather reports are measured by a thermometer called the maximum – minimum thermometer.

Most of the people in the world use the Celsius scale to measure temperature for day to day purpose. The Kelvin scale has been designed in such a way, it is not only an absolute temperature scale, but also 1^oC change is equal to a 1 K change. This makes the conversion from Celsius to absolute temperature scale (Kelvin scale) easy, just the addition or subtraction of a constant 273.15. But in United States they prefer to use the Fahrenheit scale. The problem is, converting Fahrenheit to absolute scale (Kelvin) is not easy. To sort out this problem they use the Rankine scale. It named after the Glasgow University engineer and physicist Rankine, who proposed it in 1859. It is an absolute temperature scale, and has the property of having a 1^oR change is equal to a 1^oF change. Fahrenheit users who need to work with absolute temperature can be converted to Rankine by R = F + 459.67.

Choose the best answers:

1. International unit of measuring temperature is ________________

(a) Kelvin

(b) Fahrenheit

(c) Celsius

(d) Joule

2. In thermometer when bulb comes in contact with hot object, liquid inside it

(a) Expands

(b) Contracts

(c) Remains same

(d) None of above

3. The body temperature of a healthy man is

(a) 0^oC

(b) 37^oC

(c) 98^oC

(d) 100^oC

4. Mercury is often used in laboratory thermometers because it _______________

(a) Is a harmless liquid

(b) Is silvery in colour and is attractive in appearance

(c) Expands uniformly

(d) Is a low cost liquid

5. Which of the following temperature conversions is incorrect K (Kelvin) = ^oC (Celsius) + 273.15

^oC K

(a) -273.15 0

(b) -123 +150.15

(c) +127 +400.15

(d) +450 +733.15

Fill in the blanks:

1. Doctor uses ____________ thermometer to measure the human body temperature.

2. At room temperature Mercury is in _____________ state.

3. Heat energy transfer from _______________ to ________________

4. -7^oC temperature is _____________ than 0^oC temperature.

5. The common laboratory thermometer is a ______________ thermometer.

Match the following:

i) Clinical thermometer – A form of energy

ii) Normal temperature of human body – 100^oC

iii) Heat – 37^oC

iv) Boiling point of water – 0^oC

v) Melting point of water – Kink

Answers:

Choose the correct answers:

1. Kelvin 2. Expands 3. 37^oC 4. Expands uniformly 5. +450 ^oC +733.15K

Fill in the blanks:

1. Clinical 2. Liquid 3. Higher temperature region to Lower temperature region 4. Less 5. Mercury

Match the following:

1. Kink 2. 37^oC 3. A form of energy 4. 100^oC 5. 0^oC