Module 6 Temperature

Question 1

Define temperature

Answer 1

The average measure of molecular kinetic energy within a substance

Question 2

Define heat

Answer 2

The energy a body possessed based on its temperature composting and mass

Question 3

What is the direction of heat flow

Answer 3

From a higher temperature to a lower temperature

Question 4

The rate of heat flow depends on

Answer 4

The temp difference or temp gradient

Question 5

What is Celsius scale fixed point

Answer 5

Boiling 100
Melting 0
Absolute zero -273

Question 6

What is Kelvin fixed points

Answer 6

Boiling 373
Melting 273
Absolute zero 0

Question 7

What is Fahrenheit fixed points

Answer 7

Boiling point 212
Melting point 32
Absolute zero -460

Question 8

What is Rakine fixed points

Answer 8

Boiling 672
Melting 492
Absolute zero 0

Question 9

Fahrenheit to Celsius

Answer 9

⁰F= 32 + 9/5 ⁰C

Question 10

Rankine to Fahrenheit

Answer 10

R= F + 460

Question 11

Kelvin to Celsius

Answer 11

K = C + 273

Question 12

Parts of thermometer

Answer 12

BB GEL
Bore
Bulb
Graduations
Expansion chamber
Liquid column

Question 13

Parts of thermometer

Answer 13

BB GEL
Bore
Bulb
Graduations
Expansion chamber
Liquid column

Question 14

Purpose of expansion chamber in thermometer

Answer 14

Foe liquid to expand in without exploding if upper limit is exceed

Question 15

Principle of operation of thermometer

Answer 15

Liquid in glass column expands with increase of temperature and contacts with decrease of temperature

Question 16

What are the two fixed points needed to calibrate a thermometer

Answer 16

Melting point temperature of Melting ice
Boiling point water at standard atmospheric Pressure

Question 17

The formula relating linear expansion to temperature change

Answer 17

L = L 0 (1 + αT)
Where,
L = Length of material after heating
L0= Original length of material
α = Coefficient of linear expansion
T = Change in temperature

Question 18

The amount that a solid sample will expand with
increased temperature depends on

Answer 18

the size of the sample, the material it is made of, and the
amount of temperature rise.

Question 19

Whe do solid expand

Answer 19

When heated

Question 20

Construction of Bimetal Thermometer

Answer 20

thin strips of two different metals, fused together face to face

Question 21

What principle does the bimetal thermometer depends on what principle

Answer 21

That dissimilar metals expand at different temperature rates when heated

Question 22

What happens when the bimetallic thermometer is heated

Answer 22

When heat is applied, the two metals expand
at different rates, causing the assembly to bend

Question 23

Principle of operation a bimetallic thermometer

Answer 23

The operation of a bimetallic thermometer depends on the principle that dissimilar metals expand at different rates when heated It consists of thin strips of two different metals, fused together face to face. When heat is applied, the two metals expand at different rates, causing the assembly to bend to a concave shape.
This bending motion is significant enough to drive
a pointer mechanism, activate an electromechanical switch, or perform any number of other mechanical tasks, making this a
very simple and useful primary sensing element for temperature

Question 24

Application of bimetal thermometer

Answer 24

Older home thermostats often used this principle
to both indicate room temperature and to
actuate electrical switches for controlling room
temperature.

Question 25

How to increase the sensitivity of bimetallic thermometers

Answer 25

The sensitivity of bimetallic thermometers can
be increased by building a bimetallic coil,

Question 26

Filled thermal elements make up

Answer 26

A thermal system consists of a bulb immersed
in the measuring fluid, a long capillary or fine
bore tube, a measuring unit that may be a
Bourdon tube or bellows, and a filling fluid
which may be liquid or gas.

Question 27

Filled thermal elements principle of operation

Answer 27

The bulb is inserted into a vessel or pipe where
knowledge of the temperature is required.
* Quite often, thermowells are used to protect the
bulb from erosion and corrosion.
* As the temperature at the point of measurement
increases, the liquid or gas will expand; but since
the volume is fixed, the pressure in the whole
system must increase.
* A Bourdon tube or bellows will respond to the
change in pressure by moving a pointer or
recording pen.

Question 28

Thermal filled systems are usually classed as follows:

Answer 28

Class 1 systems are completely filled with liquid
other than mercury.
* Class 2 systems are partially filled with liquid, as
shown in Fig. 4(b), and the remainder of the system
contains vapour.
Class 3 systems are totally filled with an inert gas,
such as nitrogen.
* Class 4 and 5 systems are both mercury filled. Class 4
is seldom used. Class 5 is considered a special
division of Class 1.

Question 30

Stefan Boltzman law

Answer 30

dQ/dt= eoAT⁴
Where dq/t= radiant hea loads rate
e=emissivity factor
o Stefan boatman constant
A surface area
Absolute temperature in Kelvin