# Temperature And Its Measurement ICSE Class-7th Goyal Brothers Physics Solutions Chapter-5 Unit-2

Temperature And Its Measurement Class-7th Goyal Brothers ICSE Physics Solutions Chapter-5(Heat)Unit-2(Temperature And Its Measurement). We Provide Step by Step Answers of Objectives, Fill in the blanks, Match the following, True/False, Incorrect and Correct, Question Type answers of Chapter-5(Heat) Unit-2(Temperature And Its Measurement). Visit official Website for detail information about ICSE Board Class-7.

## Temperature And Its Measurement ICSE Class-7th Goyal Brothers Physics Solutions Chapter-5 Unit-2

 Board ICSE Class 7th Subject Physics Book Name Goyal Brothers Chapter-5 Heat Unit-2 Temperature And Its Measurement Topic Solution of exercise questions Session 2023-24

### OBJECTIVE QUESTIONS

Temperature And Its Measurement ICSE Class-7th Goyal Brothers Physics Solutions Chapter-5 Unit-2

#### Que: A. Fill in the blank spaces by choosing the correct words from the list given below :

List : thermometric, kelvin, expands, 32°F, lower

1. Lower standard point on Fahrenheit scale is 32°F.

2. Mercury is commonly used as thermometric liquid as it stays a liquid over a wide range in temperature.

3. Alcohol expands more than mercury.

4. The temperature of pure melting ice is taken as the lower standard point.

5. The SI scale of temperature is called kelvin scale.

#### Que: B. Statements given below are incorrect. Write the correct statements :

##### Question: 1. 0°C is equal to zero kelvin.

Answer: 0°C is equal to 273 kelvin.

##### Question: 2. A good thermometric liquid should absorb large amount of heat energy from the body whose temperature is being recorded.

Answer: A good thermometric fluid should absorb large amount of heat energy from the body whose temperature is being recorded.

##### Question: 3. Upper fixed point on Fahrenheit thermometer is 100°F.

Answer: Upper fixed point on Fahrenheit thermometer is 212°F.

##### Question: 4. The temperature at which mercury freezes is – 93°C.

Answer: The temperature at which mercury freezes is – 38.83°C.

##### Question: 5. 1°C rise in temperature is equal to 274 K rise in temperature.

Answer: 1°C rise in temperature is equal to 274 K rise in temperature.

#### Que: C. Write ‘True’ or ‘False’ for the following statements :

 Statements True/False 1. 0°K is equal to -273°C. T 2. A thermometric liquid should have uniform rate of expansion. T 3. 284 K is equal to 11°C. F 4. Celsius scale is the SI scale for measuring temperature. F 5. Lower standard point on Fahrenheit scale is 0°F. F

#### Que: D. Tick (√) the most appropriate answer :

##### 1. Zero Kelvin is equal to :

(a) +273°C

(b) -273°C

(c) +237°C

(d) -237°C

Answer: option (b) -273°C is correct.

##### 2. SI scale of temperature is :

(a) Celsius scale

(b) Fahrenheit scale

(c) Kelvin scale

(d) None of the above

Answer: option (c) Kelvin scale is correct.

##### 3. Alcohol is used as a thermometric liquid for measuring very low temperatures because

(a) it freezes below – 100°C

(b) it is easily available

(c) it is cheap

(d) it can be brightly coloured

Answer: option (d) it can be brightly coloured is correct.

##### 4. One degree celsius rise in temperature is equal to :

(a) 1 degree rise in Kelvin scale

(b) 1 degree rise in Fahrenheit scale

(c) both (a) and (b)

(d) none of these

Answer: option (b) 1 degree rise in Fahrenheit scale is correct.

##### 5. The upper standard point on Fahrenheit scale is :

(a) 100°

(b) 180°

(c) 212°

(d) none of these

Answer: option (c) 212° is correct.

#### Que: E. Match the statements in Column A, with those in Column B :

 Column A Column B 1. A thermometric scale whose lower standard point is 273 K. (a) Fahrenheit scale 2. A thermometric scale whose lower standard point is 32°F. (b) Celsius scale 3. A thermometric scale whose lower standard point is boiling point of water. (c) Kelvin scale 4. A thermometric liquid which can measure lower temperature up to -80°C. (d) Mercury 5. A thermometric liquid which can measure temperature up to 200°C. (e) Alcohol

 Column A Column B 1. A thermometric scale whose lower standard point is 273 K. (a) Kelvin scale 2. A thermometric scale whose lower standard point is 32°F. (b) Fahrenheit scale 3. A thermometric scale whose lower standard point is boiling point of water. (c) Celsius scale 4. A thermometric liquid which can measure lower temperature up to -80°C. (d) Alcohol 5. A thermometric liquid which can measure temperature up to 200°C. (e) Mercury

### STUDY QUESTIONS

Temperature And Its Measurement ICSE Class-7th Goyal Brothers Physics Solutions Chapter-5 Unit-2

#### Question: 1. What is a thermometer? Describe briefly the construction of Celsius thermometer.

Answer: A thermometer has a glass tube sealed at both ends and is partly filled with a liquid like mercury or alcohol. As the temperature around the thermometer’s bulb heats up, the liquid rises in the glass tube. The glass tube is mounted on a backboard that is marked in units called degrees.

#### Question: 2. (a) What do you understand by the term “standard points of a thermometer?

Answer: The fixed temperatures marked on the stem of the thermometer by the common consent of scientists are known as standard points of the thermometer.

#### (b) Define lower standard point and state its value in °C, °F and Kelvin.

Answer: Lower standard point Or ice point is the temperature of pure melting ice at normal atmospheric pressure the value in C is – 273.15°C and in K is 0k.

#### (c) Define upper standard point and state its value in °C, °F and Kelvin.

Answer: The upper standard point in °C is 100°C. The upper standard point in kelvin is 373 K. The upper standard point in °F is 212 °F.

#### Question: 3. State three most important qualities of thermometric liquid.

Answer: The heat energy absorbed from the body whose temperature is being measured by the thermometric liquid should be very small. The expansion of thermometric liquid should be uniform. The boiling point of thermometric liquid should be very high and the freezing point should be very low.

#### Question: 4. Why is mercury used as thermometric liquid? Give three reasons.

Answer: Mercury is used as a thermometric liquid because of the following reasons:

1. The heat required for the expansion of mercury is very little, thus the temperature of a body can be easily recorded without changing its temperature.
2. Mercury is having a high boiling point of 357°C, so it can be used to record temperatures as high as 357°C.
3. The freezing point of mercury is -39°C, so it can record temperatures as low as -39°C.

#### Question: 5. Why is alcohol used as thermometric liquid in certain situations? Give two reasons.

Answer: Alcohol is used as a thermometric liquid in certain situations because of the following reasons:

1. The freezing point of alcohol is less than -100°C, so we can measure very low temperature using an alcohol thermometer.
2. The expansion of alcohol is more than that of mercury for the same rise or fall of temperature, hence alcohol thermometer can measure temperature more accurately.
3. The bright color of alcohol makes it easy to see on the glass capillary tube.

#### Question: 6. State the formulae for converting temperature in celsuis scale into (a) Kelvin scale (b) Fahrenheit scale.

Answer: Formula for conversion of Celsius scale into Kelvin scale:-

Temperature in kelvin scale = Temperature in Celsius scale + 273

⇒ Temperature in K = Temperature in °C + 273

Formula for conversion of Celsius scale into Fahrenheit scale:-

Temperature in Fahrenheit scale = 9C/5+32

Where C in the temperature in °C

#### Question: 7. Convert 149°F into (a) °C, (b) Kelvin

Answer: (a) Temperature in Celsius scale, C = 5/9 (F-32)

were F → Temperature in Fahrenheit scale

Temperature in Celsius scale, C = 5/9 (149-32)

⇒  C = 5/9 (117)

⇒  C = 65°C

Hence, 149°F = 65°

(b) Conversion of 149°F into Kelvin:

From (a) 149°F = 65°C

Temperature in Kalvin = Temperature in °C + 273

= 65+273

= 338 K

Hence, 149°F = 338 K

#### Question: 8. Convert -13°F into (a) °C, (b) Kelvin

Answer: (a) Temperature in Celsius scale, C = 5/9 (F-32)

were F → Temperature in Fahrenheit scale

Temperature in Celsius scale, C = 5/9 (-13-32)

⇒  C = 5/9 (-45)

⇒  C = -25°C

Hence, -13°F = -25°

(b) Conversion of 149°F into Kelvin:

From (a) 149°F = -25°C

Temperature in Kalvin = Temperature in °C + 273

= -25+273

= 248 K

Hence, -13°F = 248 K

#### Question: 9. Convert 75°C into (a) Kelvin  (b) °F

Answer: (a) Temperature in K = Temperature in °C + 273

= 75 + 273

= 348 K.

(b)Temperature in °F = 9C/5 + 32

= 9 × 75 /5 + 32

= 167 °F

Step 2: Conversion of 75°C into kelvin:

#### Question: 10. Convert -30°C into (a) Kelvin (b) °F

Answer: (a) Temperature in K = Temperature in °C + 273

= -30 + 273

= 243 K.

(b)Temperature in °F = 9C/5 + 32

= 9 × (-30) /5 + 32

= -22 °F

— : end of Temperature And Its Measurement ICSE Class-7th Goyal Brothers Physics Solutions Chapter-5 Unit-2:–-