Q: Question 3Convert 5°F to the Celsius scale.

°C = 59\dfrac{\text{5}}{\text{9}}95 (F - 32)= 59\dfrac{\text{5}}{\text{9}}95 (5 - 32)= 59\dfrac{\text{5}}{\text{9}}95 x (-27)= - 15So 5°F = -15°C.

Q: Question 4Convert 40°C to the:(a) Fahrenheit scale(b) Kelvin scale

(a) °F = 95\dfrac{\text{9}}{\text{5}}59 C + 32= 95\dfrac{\text{9}}{\text{5}}59 x 40 + 32= 9 x 8 + 32= 72 + 32= 104So 40°C = 104°F.(b) t°C = (273 + t) K= 273 + 40= 313 KSo 40°C = 313 K.

Q: Question 5Convert -40°F to the Celsius scale.

°C = 59\dfrac{\text{5}}{\text{9}}95 (F - 32)= 59\dfrac{\text{5}}{\text{9}}95 (-40 - 32)= 59\dfrac{\text{5}}{\text{9}}95 x (-72)= - 40So -40°F = -40°C.

Q: Question 8How are the Celsius and Fahrenheit scales inter-related?

°C = 59\dfrac{\text{5}}{\text{9}}95 (°F - 32)

Question 1

Question 1The temperature of a body rises by 1°C. What is the corresponding rise on the:(a) Fahrenheit scale(b) Kelvin scale?

Accepted Answer

(a) 100 divisions on the Celsius scale = 180 divisions on Fahrenheit scale1 division on Celsius scale = 180100\dfrac{	ext{180}}{	ext{100}}100180​ = 1.8 divisions on Fahrenheit scaleSo the corresponding rise on the Fahrenheit scale = 1.8°F.(b) 100 divisions on the Celsius scale = 100 divisions on Kelvin scale1 division on Celsius scale = 100100\dfrac{	ext{100}}{	ext{100}}100100​ = 1 division on Kelvin scaleSo the corresponding rise on the Kelvin scale = 1 K.

Question 2

Question 2The temperature rises by 18°F. What is the rise on the Celsius scale?

Accepted Answer

180 divisions on the Fahrenheit scale = 100 divisions on Celsius scale1 division on Fahrenheit scale = 100180\dfrac{	ext{100}}{	ext{180}}180100​ divisions on Celsius scale18 divisions on Fahrenheit scale = 100180\dfrac{	ext{100}}{	ext{180}}180100​ x 18 =10 divisions on Celsius scaleSo the corresponding rise on the Celsius scale = 10°C.

Question 3

Question 3Convert 5°F to the Celsius scale.

Accepted Answer

°C = 59\dfrac{	ext{5}}{	ext{9}}95​ (F - 32)= 59\dfrac{	ext{5}}{	ext{9}}95​ (5 - 32)= 59\dfrac{	ext{5}}{	ext{9}}95​ x (-27)= - 15So 5°F = -15°C.

Question 4

Question 4Convert 40°C to the:(a) Fahrenheit scale(b) Kelvin scale

Accepted Answer

(a) °F = 95\dfrac{	ext{9}}{	ext{5}}59​ C + 32= 95\dfrac{	ext{9}}{	ext{5}}59​ x 40 + 32= 9 x 8 + 32= 72 + 32= 104So 40°C = 104°F.(b) t°C = (273 + t) K= 273 + 40= 313 KSo 40°C = 313 K.

Question 5

Question 5Convert -40°F to the Celsius scale.

Accepted Answer

°C = 59\dfrac{	ext{5}}{	ext{9}}95​ (F - 32)= 59\dfrac{	ext{5}}{	ext{9}}95​ (-40 - 32)= 59\dfrac{	ext{5}}{	ext{9}}95​ x (-72)= - 40So -40°F = -40°C.

Question 6

Question 4gThe vacuum kept in between the walls of a thermos flask reduces the heat transfer by:conduction onlyconvection onlyradiation onlyconduction and convection

Accepted Answer

conduction and convectionReason — The vacuum kept in between the walls of a thermos flask reduces the heat transfer by conduction and convection.

Question 7

Question 6What is the Fahrenheit scale of temperature?

Accepted Answer

On the Fahrenheit scale the ice point is 32°F and the steam point is 212°F. The interval between the ice point and steam point is divided into 180 equal parts.

Question 8

Question 7What is the Kelvin scale of temperature?

Accepted Answer

On Kelvin scale ice point is marked as 273 K and steam point is marked as 373 K. The interval between the ice point and steam point is divided into 100 equal parts. 0 K is the lowest possible temperature on this scale when no molecular motion can occur.

Question 9

Question 8How are the Celsius and Fahrenheit scales inter-related?

Accepted Answer

°C = 59\dfrac{	ext{5}}{	ext{9}}95​ (°F - 32)

Question 10

Question 9How is the size of a degree defined on a Celsius scale?

Accepted Answer

The interval between the ice point and steam point is divided into 100 equal parts and each division is called a degree on a Celsius scale (1°C).

Question 11

Question 11State the temperature of:(i) ice point(ii) steam point, on the Celsius scale.

Accepted Answer

(i) On the Celsius scale the ice point is 0°C.(ii) On the Celsius scale the steam point is 100°C.

Question 12

Question 12Write down the temperature of:(i) lower fixed point(ii) upper fixed point, on the Fahrenheit scale.

Accepted Answer

(i) On the Fahrenheit scale, lower fixed point is 32°F.(ii) On the Fahrenheit scale, upper fixed point is 212°F.

Question 13

Question 13The figure shows a glass tumbler containing hot milk which is placed in a tub of cold water. State the direction in which heat will flow.

Accepted Answer

The heat will flow from hot milk glass tumbler to tub of cold water.

Question 14

Question 14Draw a neat labelled diagram of a laboratory thermometer.

Accepted Answer

Labelled diagram of a laboratory thermometer is shown below:

Question 15

Question 15Write down the body temperature of a healthy person?

Accepted Answer

The body temperature of a healthy person is 37°C or 98.6°F.

Question 16

Question 16What do you understand by thermal expansion of a substance?

Accepted Answer

The expansion of a substance when heated is called thermal expansion.

Question 17

Question 17Name two substances which expand on heating.

Accepted Answer

Iron and brass.

Question 18

Question 18Why do telephone wires sag in summer?

Accepted Answer

Telephone wires sag in summer because they expand due to rise in temperature during summer.

Question 19

Question 19Iron rims are heated before they are fixed on the wooden wheels. Explain the reason.

Accepted Answer

The iron rims are made slightly smaller in diameter than the wheel. So they are heated because iron expands and is slipped over the wheel easily, so that on cooling it contracts and makes a tight fit on the wheel.

Question 20

Question 20Why are gaps left between successive rails on a railway track?

Accepted Answer

A little gap is left between successive rails on a railway track to allow expansion of rails during summer otherwise rails will bend sideways.

Heat

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