Exsam 2 Flashcards
All electrons are attracted to?
Protons
What is the charge of an electron?
Negative
If an atom or object losers electronIs, it becomes?
Positively charged
An electric current is made up of?
Electrons moving towards a place that is positively charged.
For an electric current to flow, what two systems are necessary?
A difference in charge between two object or places.
A path for the current to fall through.
Materials which allow an electrical current to easily flow through them are called?
Conductors
To keep an electric current in its pathway, the material through which it flows is surrounded by an?
Insulator
If there are no breaks in an electrical circuit, it is said to be be?
Closed
In a parallel circuit if one appliance it tuned off, what happens to the other appliances on the circuit?
The other appliances will not be affected
What is the major danger of a short circuit?
To much current may over heart the electrical wires and cause a fire
What affects the amount of current which flows through a circuit?
The electromotive force which makes the current flow through a path.
The resistance to the flow of electrons through the path.
What measures the flow of electric current through a circuit?
Amperes
What measures the resistance to the flow of electric current through a circuit?
Ohms
What measures the electromotive force which makes the current flow through a circuit?
Volts
What measures the power used by appliances?
Watts
Does a long, thin wire have grater resistance than a short m, think wire?
Yes
An increase in the resistance of a circuit reduces?
The current flow
Does an increase in the voltage in a circuit reduce the current flow?
No
Does a 75 watt light bulb uses more power than a 40 watt light bulb
Yes
Are both wet and dry cells change chemical energy into electrical energy?
Yes.
the electrode that electrons move towards in a wet it dry cell is call the?
Positive electrode
In order for a dry cell to supply current, its inmates must be kept dry?
No
When electric current flows through a wire, it creates a magnetic field around the wire.
True
Does a generator changes electrical energy into a mechanical energy?
No
Current which flows in one direction is called?
Direct current
Does a generator produce direct current?
No
Work is done when what kinda energy is changed into the energy of motion?
Potential.
A child pulling a wagon down the street (is or is not) doing work.
Is.
The push or pull which starts or stops motion is called?
Force
Machines help make work easier by transferring or changing the direction of?
Force
A machine can save?
Effort
The ratio of useful work to the total work done by a machine is called?
Work load
The efficiency of a machine is reduced by?
Friction
A gasoline engine is more or less efficient than a turbine?
Less
Bicycles are an example of what kinda machines?
Complex
Solar energy (is or is not) difficult to store?
Is
Water energy is harnessed by?
Turbines
Do Internal combustion engines run on exploding gas?
Yes
Under certain conditions, matter can be changed into energy, and energy changes In to?
Matter
The nuclear reaction in which energy is released by the splitting of nuclei of heavy atoms is called?
fusion
In atomic fission, crew chain reaction occurs because of?
fast moving neutrons
Nuclear reactors currently obtain what energy from?
fission
Fission is the nuclear reaction which uses the least expensive materials and produces the least amount of radioactive by- products?
False
A centimeter is used to measure?
Length
A kilogram is used to measure?
Weight
The abbreviation g stands for?
Gram
The abbreviation cm stands for?
Centimeter
A liter a larger than a?
Milliliter
A kilometer is larger than?
A meter & a millimeter
A gram is smaller than?
Kilogram
20 kilometers equals how many kilograms?
20,000
6000 grams equals how many kilograms?
6
