Thermal Physics

Question 1

Explain thermal equilibrium

Answer 1

When energy is transferred from a region of high temperature to a region of low temperature
And went two objects are in contact with each other and they are both the same temperature. There is no energy between them.

Question 2

How do you convert from degrees Celsius to kelvin?

Answer 2

T (k) = theta +273

Question 3

What is the Celsius scale based on?

Answer 3

The Celsius scale is based on the boiling and freezing point of water which depends on pressure 

Question 4

Describe the structure of solids

Answer 4

The particles vibrate in a fixed regular lattice when temperature increased the amplitude of the vibration increases and the spacing between the particles is small

Question 5

Describe the structure of liquids

Answer 5

The particles can flow past each other they vibrate but not in a fixed position and a spacing between the particles is slightly larger than solids

Question 6

Describe the structure of gases

Answer 6

The particles are far apart and they don’t exert any forces on each other except in collision and the particles move in random linear motion

Question 7

Describe the observations and conclusions of the brownian motion

Answer 7

A smoke cell is viewed in a microscope can also be pollen grains
And the smoke particles are seem to be moving in a random linear motion
This is because the smoke particles are colliding with air particles which cannot be seen therefore the particles are also moving in a random linear motion
Another conclusion is that the particles must be a lot smaller than the smoke particles 

Question 8

Define internal energy

Answer 8

Internal energy is the sum of randomly distributed kinetic and potential energies of the particles of a substance

Question 9

Define specific heat capacity

Answer 9

The energy required to raise the temperature of 1 kg of substance by 1 K

Question 10

How do you reduce the uncertainty in the specific heat capacity experiment?

Answer 10

Stir the liquid regularly as the temperature of the liquid will be uneven 

Question 11

Describe the experiment for the specific heat capacity of liquid

Answer 11

Measure the mass of the liquid using a top pan balance
Measure the current with an ammeter
Measure the voltage with a voltmeter
Measure the temperature on sat with a thermometer
Measure the set intervals with a stop clock
Then plot of temperature against time
Then rearranged the equation so that the specific heat capacity equals power divided by mass times gradient
 calculate power by doing P equals IV 

Question 12

Define specific latent heat

Answer 12

Specific latent heat of a substance is the energy per kilogram required to change its state without any change in temperature

Question 13

Describe specific latent heat of fusion and specific latent heat of vaporisation

Answer 13

The specific latent heat of fusion is the energy per kilogram required to melt a substance at a constant temperature
The specific latent heat of vaporisation is the energy per kilogram required to vaporise a substance constant temperature

Question 14

Describe the experiment for specific latent heat of fusion

Answer 14

Set up the operators with two funnels full of ice one that is heated and one that is left at room temperature then place beakers underneath the funnels
Measure the current with an ammeter measure the voltage with the voltmeter and let the heater melt the ice for a certain amount of time which is measured with a stop clock
One of the funnel should be left at room temperature
Then use a balance to measure the ice that melted from both beakers and subtract the mass of the ice melted from the control which was left at room temperature
Then use equations

Question 15

State Boyle law

Answer 15

Pv=constant
Pressure and volume are inversely proportional

Question 16

A camping kettle was used to heat up some water and placed in a cup the minimum time taken for the camping kettle to bring a cup of water at 20°C to boiling point was about 200 seconds however in a laboratory test the cat was found to bring a cup of water to boil in 320 seconds. Explain why the 200 seconds was an underestimate and suggest two ways you can refine the test.

Answer 16

Some thermal energy will be lost to the cattle and the surrounding air to prevent this the kettle can be insulated and a lid can be put over the kettle to prevent evaporation

Question 17

State the observations and conclusions associated with brown in motion when smoke particles suspended in air or observed in the microscope

Answer 17

Smoke particles move in a random zigzag path as they are colliding with particles which we cannot see

Question 18

A tube containing small pellets of lead were inverted and the lead fell freely through vertical heights equal to the length of the tube. The pellets are warm after the tube has been inverted many times the specific heat capacity of lead was calculated from the given information state two assumptions made in this calculation.

Answer 18

No energy is dissipated to the surroundings. No heat is absorbed by the tube.