Thermodynamics
Why is it that you can hold something as cold as dry ice briefly?
Because it takes time for the energy (in this case molecular kinetic energy/warmth) of your hand to transfer to the ice
What does it mean when a process is Isochoric?
Constant Volume
What happens when a charged object is brought near a neutral object and why?
The neutral object becomes attracted to the charged object due to polarization
What does a capacitor do in a circuit?
It stores charge
How does Earth’s magnetic field flow from its poles?
It flows from the North pole to the south, all magnets do
When an object is heated, what happens to its volume? Is the rate of change the same for everything?
It expands, and no
For Fahrenheit, Kelvin, and Celsius: arrange them from least to greatest in terms of the size of the units.
F<C=K
What are examples of the two types of charging?
Conduction: Rubbing hair on a balloon
Induction: Lightning
Is high voltage or current more efficient in transmitting power?
Low current and high voltage is most efficient due to joule heating (P=I^2 R)
What are ways that you can increase the strength of an electromagnet?
Increase current
Increase number of turns in coil
Insert an iron core
What is calorie a unit of?
Heat
Remember can be calories can be converted into joules.
Rank the following in terms of increasing internal energy, and then in terms of entropy: Honey, Ice, Water, Air
Both should end up the same:
Ice<Water<Honey<Air
Remember the size/complexity of an molecule means more heat and more entropy
At what speed do electrons and the electric field move?
Electrons move at drift velocity while the electric field moves near the speed of light
What are factors that affect resistance?
wire thickness (when thickness increases resistance decreases), material, length (longer means more resistance), temperature (higher temp means more resistance)
If a particle is in a magnetic field and is experiencing the maximum force, is it moving along with, perpendicular, or against the magnetic field?
Perpendicular
At what temperature is water densest (when is its volume the smallest)?
At 4 degrees Celsius
When water evaporates, what is the amount of energy absorbed by the water from its surroundings?
Latent Heat of Vaporization
Are two wires carrying current in the same direction attracted to each other or repelled?
Attracted
If there are two bulbs in series, if one breaks what will happen to the remaining bulb?
It will go out because the circuit is no longer closed
How does the magnetic field look like when a current is flowing through the wire?
It circles around the wire
When you have condensation on a cold drink, what does the transfer of energy look like?
Water from air releases energy (gas to liquid)
Drink absorbs that energy
Warming process for the drink
What is the difference between heat capacity and specific heat? What does it mean to have a high specific heat?
They are effectively the same thing, it’s just that heat capacity already to into account the object in question, while specific heat is ironically more general and you have to specify the mass of the object
A high specific heat means that the substance heats slower but retains heat longer, and vis versa for low specific heat
What direction do electric field lines point in a dipole? Where is the electric field the strongest?
From + to -
In between the charges/where the lines are closest together
To minimize resistance, should two bulbs be placed in series or in parallel?
Parallel
1/rtot=1/r1 + 1/r2
What is the difference between a step up and step down transformer?
Step up: primary coil has less turns than the secondary and voltage increases
Step down: primary has more turns than secondary and voltage decreases