Science CHPT. 19-20 Flashcards
What is electrical force?
the force between two charged objects. It could be an attraction or repulsion. Sometimes objects touch, sometimes they don’t
What creates a repulsive electrical force?
Two objects with like charges.
How do you double the force on two objects?
By doubling the force on one of the objects.
*If you double the force on both objects, the force is quadrupled.
How do you reduce the force on an object?
By increasing the distance, the force is reduced. Ex. if the distance is doubled, the force is reduced by 1/4.
What is an electric field?
A 3D region around a charged object that applies force on other objects in that region.
What is current electricity?
Electricity involving moving electrical charges.
What is an electric current?
The movement of an electric charge through a complete loop.
What is an electric circuit?
The loop through which current electricity can flow.
What is the difference between and open and closed circuit?
open: incomplete, preventing the movement or flow of charge
closed: complete and allows current
What is the difference between direct current and alternating current?
direct: charges flow in one direction
alternating: electric charges that change directions repeatedly as the system operates. Electrical outlets in homes.
What is voltage?
The force that moves electric charge carriers through an electric circuit. the unit for electrical potential difference is called “volt.”
What is an electrical conductor?
Materials through which charge moves easily. These are used to make sure charge goes where we want it to go.
What is a semiconductor?
Sometimes conduct current, sometimes don’t. Typically, conductivity increases with temperature
What is an electrical insulator?
A material through which charge flows poorly. These are used to prevent current from going to the wrong place.
What is a superconductor?
materials with zero resistance
What is a short circuit?
When the current takes an unintended path. This is dangerous.
What are some safety devices to prevent a short circuit?
fuse: opens the circuit by melting. Must be replaced
circuit breaker: automatic switch that opens when there is too much current. Doesn’t have to be replaced.
ground prongs or wires: runs electricity to the ground. Doesn’t have to be replaced.
ground-fault interrupter (GFI): built in circuit breaker. Doesn’t usually have to be replaced.
What is the difference between a series circuit and a parallel circuit?
Series: only one path for the charge carriers to move through. all current must flow through each component.
parallel: branches that provide multiple paths that current can take. This allows one thing to work when another stops working. (ex. when a lightbulb above your vanity burns out but the rest continue to work)
Compare the geographic poles with the magnetic poles.
The geographic poles are fixed but the magnetic poles are constantly changing location. The earth’s magnetic south pole is actually a north magnetic pole.
A metal rod is rubbed with flannel cloth and the cloth became positively charged. How did this happen?
The metal rod lost electrons to the cloth.
What is a magnet?
any material or object that can produce a magnetic field.
What is a magnetic field?
the region surrounding the magnet where it can exert a magnetic force. Magnetic field forces always point toward a south magnetic pole. Flowing current in a wire always produces a magnetic field.
Earth’s magnetic field most likely originates from deep inside the earth due to the flow of liquid iron in the outer core.
Describe the relationship between a bar magnet and a coil of wire?
A bar magnet will induce an electrical current in the coil of wire when the bar magnet is moving through the coil
How can electromagnets increase in strength?
Increase the number of loops in the wire coil or increase the current in the wire coil.
