Thermal Physics

Question 0

What is convection?

Answer 0

Hot fluid rises, cold fluid sinks, because the hot fluid is less dense than the cold fluid. Only in fluids. Causes convection currents.

Question 1

What is conduction?

Answer 1

Transfer of energy through collisions of vibrating particles. Happens in solids and liquids, increased in metals because of free electrons.

Question 2

What is infra-red radiation?

Answer 2

Black objects absorb and emit radiation more efficiently. Shiny objects deflate them best. Only energy that travels through a vacuum. Travels at speed of light, x10-4.

Question 3

What is evaporation?

Answer 3

When a particle gains enough energy through heating that the kinetic energy is sufficient for it to leave the liquid & become a gas. They condense when they cool.

Question 4

What is thermal energy?

Answer 4

Energy transfer between two objects or within an object from a region of higher temperature to an area of lower temperature.

Question 5

What is temperature?

Answer 5

The property of an object that determines the direction of thermal energy transfer.

Question 6

What is internal energy?

Answer 6

The sum of kinetic and potential energies of all the particles in a substance/object.

Question 7

Temperature in kelvin?

Answer 7

Temperature in •C + 273.15.

Question 8

Definition of Specific Heat Capacity?

Answer 8

The energy needed to raise the temperature of a unit amount of material by a unit temperature.

Question 9

How do you calculate energy?

Answer 9

E = mc^0

Question 10

Definition of specific latent heat?

Answer 10

The energy required to change the state of 1kg of a material without a change in temperature. Units: Jkg-1

Question 11

Equation for specific latent heat?

Answer 11

E = mL(v or f)

Question 12

Define Brownian motion.

Answer 12

The observed continual random motion of any small particles suspended in fluid. This is because of the collisions of air or water molecules with the particle.

Question 13

What is the gas constant?

Answer 13

P1V1/T1 = P2V2/T2.

Question 14

What is Charles’ Law?

Answer 14

P1=P2 so V1/T1=V2/T2

Question 15

What is the pressure law?

Answer 15

V1=V2 so P1/T1=P2/T2.

Question 16

What is Boyle’s Law?

Answer 16

T1=T2 so P1V1=P2V2.

Question 17

What are the ideal conditions for a gas?

Answer 17

+ Collisions between atoms are elastic.
+ Time between collisions is negligible compared with time of collisions.
+ Motion of atoms is random.
+ There are a large no of atoms.
+ Forces between atoms are negligible except during collisions.

Question 18

What are the equations for the ideal gas?

Answer 18

pV=nRT
Where n = no. mols. 
pV=1/3Nmv^2
Where Nm=total gas mass. 
pV=1/3Nmc^2
p=1/3/p/c^2 
Where /p/ = density.

Question 19

What is the equation for K.E. of a gas?

Answer 19

Ek=3/2KbT

Where Kb=Boltzmann’s Constant (1.38x10^-23).

Question 20

What is Avogadro’s Constant?

Answer 20

Na=6.02x10^23

Question 21

What is the R constant?

Answer 21

8.31.