Final 1

Question 1

What Direction is the Force of a current-carrying wire?

Answer 1

Perpendicular or at right angle to both the MF and the Current.

Question 2

If your fingers are pointing upward and your thumb is pointing to the right, what direction is the force?

Answer 2

Towards you

Question 3

Altern­ating Current

Answer 3

Current that’s direction changes over time. The voltage across the resistance goes up and down.

Question 4

Transf­ormer

Answer 4

A device that uses electr­oma­gnetic induction to change the size of a voltage for an altern­ating current.

Question 5

Induced Electr­omotive Force

Answer 5

The generation of a potential difference in a coil due to the changes in the magnetic flux through it measured in Volts

Question 6

Kirchh­off’s First Law (Junction or node Law)

Answer 6

The sum of currents flowing into the node is equal to the sum of currents flowing out of the node

Question 7

Kirchh­off’s Second Law (the loop)

Answer 7

The sum of all voltages around a closed loop in any circuit must be equal to zero, meaning the net change in voltage should be zero

Question 8

Magnetic Flux

Answer 8

The number of flux lines through a certain area

Question 9

Electromagnetic Induction

Answer 9

The process of generating a current through a wire in a circuit in a mag. field

Question 10

Voltage Divider

Answer 10

A circuit that produces a potential difference that is less that what its source provides

Question 11

What would removing a resistor in a parallel circuit affect?

Answer 11

The overall current but not the current in another branch because current depends on the voltage, which is equal everywhere, and the resistance of each individual resistor, which is different in every branch.

Question 12

How would adding more devices in a series affect the current?

Answer 12

It will decrease the current,

Question 13

How does a light meter use a photoresistor?

Answer 13

photoresistor is a sensor that changes its resistance when light shines on it. The resistance generated varies depending on the light striking at his surface. A high intensity of light incident on the surface will cause a lower resistance, whereas a lower intensity of light will cause higher resistance.

Question 14

Short Circuit

Answer 14

When the current used exceeds the current supplied causing it to malfunction or light on fire due to the extra thermal energy from the extra current

Question 15

Types of Safety in Circuits

Answer 15

1) Fuse: Melts when the current exceeds its limit

2)Circuit Breaker: An automatic switch that disconnects the current flow by opening when it detects too much current

3)Ground Fault interrupter: Breaks the current when it detects a new path or a difference in the current implying either a fire, extra demand or electronization.

Question 16

Power (watts) Formula

Answer 16

P = I X V

Question 17

Ammeter

Answer 17

• Measures Amps
• Placed in Series
  -Low resistance

Question 18

Voltmeter

Answer 18

-measures Voltage
- Placed in Parallel
- High resistance

*Connecting it across a resistor will lower the potential difference

Question 19

Polarization

Answer 19

The alignment of domains

Question 20

Solenoid Facts

Answer 20

• Each loop in a solenoid has its own MF but together they are in the same direction
• A computer has a solenoid in its hard-drive to record information on a spinning desk

Question 21

Speed in Electric Motors

Answer 21

Can be controlled by varying the frequency at which the current alternate

Question 22

Levetation

Answer 22

The repulsion of two objects that one of them carries an opposing magnetic field due to the it being induced by an EMF opposing the original one due ot Lenz’s law, Which causes the two of them to repel since they would be facing ear other’s like poles. The MagLev trains use it to elevate the trains off of the tracks

Question 23

Lez’s Law

Answer 23

It states that a induced magnetic field should always oppose the direction of its original magnetic field to avoid the line up of the two magnetic field that will result in infinite, never-ending cycle of inducing the magnetic flux and current which oppose the law of Energy Reservation

Question 24

How Does Lenz’s Law affect Generators and Motors?

Answer 24

For generators, the induction of an opposing magnetic field will result in a higher resistence which will slow down the movement of the armature.
For Motors; it will help decrease the initial high current.

Question 25

Eddy’s Currents

Answer 25

They are loops and whirpools of electrical current that are induced by the fluctuation of a magnetic field whihc they will run perpendicular to.

Question 26

The Eddy Current Damping Effect

Answer 26

It’s the slow doen of movement due to the high resistance that the extra produced currents results in, it’s used to slow down trains and roller coaster. To reduce its effect, motors use thin materials that can not hold high amount of eddy currents.

Question 27

Self-Induction

Answer 27

The ability of a wire or a coil to produce an opposing EMF if it faces a change in current that result in a magnetic field flux to decrease or increase the change that happens.

Change Change Opposing
In —–> In ——-> EMF
Current Flux Produced

Question 28

Isolation Transformers

Answer 28

Transformers have no power of stepping up or down, so zero change i the input. They are used for safety reasons mostly

Question 29

Mutual Inductance

Answer 29

And EMF and Current produced in a coil due to a change in another coil.

Question 30

How does A Synchrotron apply the rules of magnetic fields

Answer 30

It had a magnetic force which causes the charges to accelerate and move in a circular path