chapter 17 effect heat and its transmission Flashcards
What is the SI unit for temperature?
Kelvin (K)
When a substance increase volume its called _____ and when something decrease volume its called _____
(i) expansion
(ii) contraction
what are the examples of expansion and contraction in real life?
- telephone wires and electricity cables
- tiled and concrete pavement
- laboratory glassware
- water pipes
- MRT and railway tracks
- bridges and metal gliders
A bimetallic strips consists of two metals. If iron was the top strip and brass was the bottom strip, when the bimetallic strip is heated, which way would it bend?
the bimetallic strip would bend downwards because brass expands more than iron when being heated
How does heat flow?
from a region of higher temperature to a region of a lower temperature
Define conduction.
Conduction is the process of heat transfer through a material or a medium without any movement of the material or the medium
state some examples of bad heat conductors (insulators).
wood rubber plastic glass water air asbestos
what is a better conductor of heat, solid, liquid or gas?
solid
define convection.
the transfer of heat from one place to another by the movement of fluids ( liquid and gas)
How does household ventilation work with convection?
the air conditioner cools the hot air which then becomes denser and sinks to the bottom of the room. the hot air rises as it is less dense than the cool air and the cycle continues until the whole room is cooled
define radiation.
radiation is the transfer of heat in the form of waves, from one place to another. It does not require a medium for transmission
how a body radiate heat depends on…..?
- nature of the surface of the body
( black or white or coloured or smooth or shiny) - total surface area of the body
- the temperature of the body
