# Physics test 5

version from 2015-12-04 03:09

## Section

The only NATURALLY occurring magnetic elements are (3)iron, nickel, and cobalt
The two ends of a magnet are called _ and _. North Pole - South Pole
Magnet poles are _ and they will remain the sane even if you break them apartPermanent
Do mono-pole magnets exist?No
Magnets are surrounded by M_ F_ which point from the _ pole towards the _ pole of the magnetMagnetic Fields - North - South
T or F. Stationary charges produce a fieldFalse, the motion of the charges produce the magnetic field
Direction of a magnetic field in a electric current is given by the _ _ Rule which states ?Right hand Rule - With you thumb pointed towards the direction of the current, your fingers wrapped around the wire show the direction of the magnetic field
Magnetism on the atomic level happens how? (Example)The orbits of the e- aligning their orientations. (Think of an eclipse)
Define - ElectromagnetA magnet charge that is induced ONLY when an electrical charge passes through it
Wires will attract each other when the currents are running in the _ direction as one anotherSAME
What is a superconductor?Conductors with NO resistance
T or F.Under normal conditions, all conductors exhibit resistance to the passage of e-. Explain your answerTrue, the e- passing through wires collide with other atoms and some of their KE changes into heat
T or F. Magnetic force is perpendicular to the flow of a charged particle.True
Magnets apply a _. This is so because on Newton' s _ LawForce - 3rd
Two wires that are parallel and running current in the same direction will be _ to one-anotherAttracted
Unit for magnetic field strengthTesla (T)
Once a current in a superconductor has been established, it will persist without any applied _Voltage
T or F. Power-lines lose a lot of electricity due to the resistance they create (heat, cracking, etc)True
Is the "North Pole" a N or S magnet pole?South, this is because it ATTRACTS North poles of compasses
The magnetic force on a charged particle is _ UNLESS the particle is _0 - moving
In a magnetic field a electrical wire with moving charged particles (e-) are all moving in one direction experience a magnetic field that is _ to the velocity of the particles and _ to the magnetic fieldPerpendicular - Perpendicular
Max. Magnetic force equation(q)(v)(B)(sine(ѳ))
When the velocity and the magnetic field are PARALLEL the force is _ and the velocity will be in a S_ L_0 - Straight Line
If the velocity of a charged particle is perpendicular to a magnetic field the _ will change and it will move in a _direction - circle
If the velocity of a charged particle is at a less than a 90ѳ to a magnetic field it will movie in a _ motion (EX)Helical (path along a stretched out spring)
Explain the northern lights (Aurora Borealis)The collision of cosmic rays colliding with earths magnetic field which causes them to move in many varying helical paths
Can a magnetic field produce an electrical current? If so, how?YES. If you move a wire PERPENDICULARLY to a magnetic field you will get a current because of the force exerted on the wire from the magnetic field. AMAZING....
How does an electromagnet produce an electrical current while remaining still?By changing the magnetic field you can produce a current due to Newton's third law
Lenz's Law - DefineThe current always produces a magnetic field to oppose the change that created it
How do transformers work?a rectangular iron core is wrapped on one side with MANY loops of copper which is magnetized by a power line with a large voltage. The opposing side of the core wrapped with less loops. The alternating current being received by the side with MORE loops produces an alternating magnetic field which in turn causes the side with LESS loops to transmit a current with LESS voltage to a home.
Why would a transformer NOT work with DC current?It is the AC current passing through the wires that causes the magnetic field to alternate and produce a current. If you had a steady stream of current as in DC you would have no current created
What is a generator? How does it work?Converts ME into Ele energy - Produces electricity by rotating a coil in a STATIONARY magnetic field
What is a motor? How does it work?Converts Ele energy into ME - A current is passed through a coil which forces the coil to spin
Ferromagnetic - Define (EX)A material that is HIGHLY susceptible to being magnetized and can stay magnetized for a time AFTER a magnetic field is no longer present (Iron)
T or F. Magnetic fields are produced by a CHANGING ele. fieldTrue
A changing magnetic filed will produce an ele. field in E_ S_ regardless if a W_ is presentEmpty Space - Wire
As an electrical field increases and decreases between two parallel plates (not touching) it will produce a magnetic field in _ directionsOpposite
A changing E_ field produces a _ field and a changing M_ field produces a _ field. These fields alternate in D_ as the original field gets _ or _Electrical - Magnetic - Direction - bigger - smaller
T or F. If you change an ele field in a constant rate you will get a magnetic field of a constant amount. The same is true of magnetic fieldsTrue
Remember C=λfGot it
Difference between AM and FM Radio broadcastingIn AM the amplitude changes. In FM the frequency changes
T or F. A compass placed around a magnetic field surrounding a wire will face TOWARDS the wire.False, it will point if the direction of the current; tangent to the circle (parallel to the wire at all points)
Emission Spectrum - Define - when do they occurThe distinct VISIBLE line pattern of colors given by a particular gas - occurs when am e- goes from a higher energy level to a lower one
Absorption Spectrum - Define - When do they occurThe distinct MISSING line pattern given by a particular gas - occurs when an e- moves from a lower to a higher energy level
What is a cathode ray?A huge voltage sent into a negative cathode is shot across a vacuum chamber and is seen in a corresponding positive anode (name for the Pos. receiving cathode).
Does a magnetic field exert a force on a beam of light?No
Quanta - DefineA packet of energy; The smallest measurement of energy.
T or F. A Quanta can be splitFalse, this is the smallest division of electrical charge
Elements are defined their number of _. Elements of close atomic _ have similar attributesprotons - number
Radioactivity - defineThe spontaneous emission of fast moving atomic particles from certain elements
Alpha Particles - DefineThe nucleus of a He atom
Nucleus - DefineThe center of an atom consisting of the protons and the neutrons which is net positive
Atoms are almost entirely _ _Empty space
energy of a Quantum EquationE=hf (h is planks constant 6.626x10^(-34) j*s
What is the Photoelectric effectWhen light is shined on certain metals e- are ejected from the surface
Photons - defineLight itself is energy; light is a specific amount of quanta
Why do different colors of light have different photoelectric effect amountsDifferent colors are different frequencies and these different frequencies have different amounts of light. THEY DO NOT HAVE DIFFERENT AMOUNTS OF QUANTA
Electron VoltKE acquired by an e- falling through a potential difference of 1 volt
What are X-rays? When were they first discovered?High frequency electromagnetic radiation. - First seen when the e- in the cathode ray are slowed down as they crash into the metal target inside the tube
IonA charged particles; An atom with missing or extra e-
Explain how an e- changes shellsIf energy is sent INTO an orbiting e- the e- will absorb the energy and move UP one or more shells. If energy is RELEASED from an e- it will DROP into a lower shell
T or F. Radioactivity is a nuclear effectTrue
What is the difference between a nuclear effect and an atomic oneAtomic effects change when the element undergoes a chemical reaction while atomic ones do not.
What is the strength of Alpha Radiationweak, it will not even go through paper
What is the strength of Beta RadiationStrong, it will go through a meter of air or even some thin metals
What is the strength of Gamma RadiationVERY strong, it can go through many meters of air or through even thick walls
What governs the chemical properties of an elementthe e-
What is an Isotope?Atoms having the same number of Protons but DIFFERENT numbers of Neutrons
What is a nucleon? The lowest 1-1 ratio of Protons and Neutrons in a Nucleus
What is Beta - Decay?A neutron is lost and a proton appears and the process produces an electron and electron anti-neutrino
What is Beta + Decay?A proton is lost and a neutron appears and the process produces a positron and electron neutrino; β+ decay is thus also known as positron emission