Honors Physics Conceptual Physics Chapter 36/37 Review
Terms in this set (36)
What is the source of all magnetism?
Motion of electric charge
What phenomenon are around all moving charges?
What are all the possible interactions between the poles of magnets?
Attract and repel
What is a fundamental difference between positive and negative charges and north and south poles?
Electric charges can be isolated but magnetic poles can not
What happens to a compass placed in a magnetic field?
Lines up with the magnetic field
Describe the strength of a magnetic field around a magnet
Stronger at the poles, weaker when opposite to the poles
What are magnetic domains?
Clusters of aligned atoms
What does a magnetic field look like around a wire?
The compasses align with earth's magnetic field
What happens to the magnetic field around a wire when the wire is bent?
The magnetic field lines become bunched up inside the loop
What materials are needed for an electromagnet?
A current carrying coil of wire with many loops
How do the magnetic poles of earth compare to the geographic poles?
Magnetic and geographic poles do not coincide, the magnetic poles in the north are located some 800 km from the geographic north, the southern magnetic field is just off the coast of Antarctica
What causes the earth to have it's magnetic field?
Moving charges looping around within earth
Why is the difference between the geographic north and the compass reading called?
What direction do the field lines move in a magnet?
North to south
Describe what happens to a wire placed in a magnetic field when current passes through the wire in both directions
The wire experiences deflecting forces
What is necessary to induce a current in a wire with a magnet?
Movement relative to eachother
How is the number of coils related to the induced voltage?
The greater the number of loops of the wire that move in a magnetic field, the greater the induced voltage in the wire
How can the field strength of a coil of wire be increased?
Increased loops and increased current
How are motors and generators similar and different?
Motor converts electrical energy into mechanical energy, generator converts mechanical energy into electrical energy, they are both made up of wires and magnets
How can the current in a coil of wire be increased?
More coils of wire or move them faster
What are the most common ways to rotate a generator and which method is the most common?
Wind, water, steam-most common
What is the primary purpose of a transformer?
Step up or step down voltage
What is the difference between a step up and a step down transformer?
Step up- increases from primary to secondary
Step down- decreases from primary to secondary
Define electromagnetic induction
Phenomenon of inducing voltage by changing the magnetic field around a conductor; electric current can be produces in a wire by simply moving a magnet into or out of a wire coil.
Magnetic field (tesla)
Number of turns
A machine that produces electric current by rotating a coil within a stationary magnetic field.
motor Vs Generator
whereas a motor converts electric energy into mechanical energy, a generator converts mechanical energy into electrical energy.
states that induced voltage in a coil is proportional to the product of the number of loops, the cross sectional area of each loop, and the rate at which the magnetic field changes within those loops.
A device for increasing or deacreasing voltage through electromagnetic induction.
How does a transformer work.
It works by inducing a changing magnetic field in one coil, which induces an alternating current in a nearby second coil.
primary and secondary coils and transformers.
Primary coild = input secondary = output.
How does a magnetic field affect a moving charge?
moving charges experience a force that is perpendicular to both their motion and the magnetic field they trevers.
induction of electric and magnetic fields.
a magnetic field is created in any region of space in which an electric field is changing with time; there is a symmetry between electric and magnetic fields r.e. Faraday, Maxwell.
is composed of oscillating electric and magnetic fields that regenerate each other. no medium is required. the oscillating fields move outward from the vibrating charge.