1 Flashcards
What are the three temperature scales mentioned?
Celsius, Fahrenheit, Kelvin
These scales are used to measure temperature.
How is heat defined?
Heat is energy which flows from a hot body to a cold body
Heat is a form of energy.
What happens when two bodies at different temperatures are in contact?
Energy is transferred from the hot body to the cold body
This process results in the cold body warming up and the hot body cooling down.
What is the SI unit of heat?
Joule (J)
The CGS unit of heat is erg.
What is the relationship between calories and joules?
1 cal = 4.186 J
This is an approximate conversion.
What are the other units of heat besides joule?
Calorie (cal), Kilocalorie (kcal)
1 kcal = 1000 calories.
Fill in the blank: Heat energy is the internal energy of ______.
molecules of a body
The molecules are in random motion.
True or False: A hot body has less internal energy than a cold body.
False
A hot body has more internal energy than a cold body.
What causes heat to be produced in a metallic wire when an electric current passes through it?
Electrical energy
Heat is obtained from electrical energy due to resistance.
What is the effect of rubbing palms together?
Heat is produced by doing work
This is an example of mechanical energy being converted to heat.
When touching warm water, why do we feel hot?
Heat energy from warm water passes to our hand
This exemplifies heat transfer.
What happens when we touch a cube of ice?
We feel cool because heat energy from our hand passes to the ice
This again illustrates heat transfer.
What is the concept of thermal expansion related to?
The thermal expansion of solids
Heat affects the motion of molecules in solids.
Fill in the blank: The internal energy of a cold body ______ when in contact with a hot body.
increases
This occurs while the hot body’s internal energy decreases.
What is the primary cause of heat in burning coal?
Chemical energy
The chemical reaction releases heat energy.
