Statistics for Generating Electricity

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General Stats

This quiz has been taken 7 times
The average score is 6 of 32

Answer Stats

Question	Answer	% Correct
What device is used to detect small electrical currents?	Galvanometer	67%
Who discovered the motor effect?	Michael Faraday	67%
Magnetic field lines move away from which pole	The North Pole	50%
What does emf stand for?	Electromotive force	33%
What is the name given to the amount of magnetic flux through a given area?	Magnetic flux	33%
In Faraday's initial experiment with two separate coils, there was a current induced into the coil with no battery. However this current was only _________.	Temporary	33%
What is magnetic field strength, B, measured in?	Tesla (T)	33%
In electric motors, an induced emf is created in the current-carrying coil because it is moving in a magnetic field. What direction compared to the current is the emf travelling?	The opposite direction	33%
When a load is added the coil rotates slower so back emf is reduced. This results in a higher current which could burn out the motor. What device is used to protect motors from an initially high current when they are switched on?	A series resistor	17%
What is this emf also known as?	Back emf	17%
When this happens no voltage and therefore no current passes through the coil. There is also now no net force on the coil so it rotates at a ________ ____.	Constant rate	17%
What is created every time a conductor moves through an external magnetic field or vice versa? They are an application of Lenz's Law.	Eddy currents	17%
What is the name for the generation of an emf through the use of a magnetic field?	Electromagnetic Induction	17%
	Flux	17%
Lenz's Law: An induced current always _____ ___ to a current that creates a magnetic field that _______ the original change in ____ through the circuit.	Gives rise	17%
A faster moving magnet near a coil induces a ______ current.	Larger	17%
	Opposes	17%
What direction do these produced magnetic fields travel compared to the external magenetic field direction. (They travel in circles/whirls)	Perpendicular	17%
What is emf is inversely proportional to?	The change in time	17%
What law is Lenz's Law a consequence of?	The law of conservation of energy?	17%
Compared to moving a magnet into a coil, what direction does the deflection in the galvanometer read when the magnet is brought away from the coil.	The opposite direction	17%
It's symbol is the greek character phi, but what is it's SI unit?	Weber (Wb)	17%
By switching on an electromagnet close to a wheel, what can we use eddy currents for in cars and trains?	Electromagnetic breaking	0%
These devices create electromagnetic fields to induce eddy currents into detectable metals. These eddy currents place a load on the coil, changing the _________ of the oscillator.	Frequency	0%
Eddy currents also cause an increase in ____ which can be helpful in the kitchen.	Heat	0%
The process of using this property in induction cookers and furnaces is called what?	Induction heating	0%
Faraday's second notable experiment on induced currents featured an ____ ____. This had a greater induced current but it was also ^.	Iron ring	0%
What is magnetic field strength is also known as when it passes through a given area?	Magnetic Flux Density	0%
What is the most common example of an induction switching device?	Metal detector	0%
In other words an "induced" magnetic field ______ what causes the change in flux through a circuit.	Repels	0%
If there is nothing to slow it down, the speed of the armature coil in a motor increases until the back emf is equal to what?	The external emf	0%
What is the magnitude of generated emf is determined by?	The rate at which the magnetic flux changes	0%