End Of Year Exam Flashcards
(17 cards)
What is an NTC resistor?
An NTC resistor is a thermistor for which resistance drops as temperature rises.
What is emf?
It is defined as the energy transferred from chemical/another form to electrical energy per unit charge. (e.m.f= energy transferred/charge)
What is the formula for work done on an electron in an electron gun?
Work done on an electron= final kinetic energy of an electron
V x e =1/2 mv^2 ( V being the p.d)
What are the Si units of a volt.
kgm^2s^-3a^-1
How can one work out the work done on a piece of wire - where it’s being stretched?
Work done = area under graph
How is voltage defined?
V=W/Q (voltage =energy transferred per unit charge
What is the difference between the emf and pd?
EMF = energy transferred to store
P.d = energy transferred from store
What is Kirchoff’s first law?
Learn word for word
For any point in an electrical circuit the sum of currents into a point is equal to sum of currents out of a point.
What is Kirchoff’s second law?
Learn off by heart!
Sum of emfs in a closed loop = sum of pds in closed loop
What is the definition of internal resistance?
The resistance of a source of emf (e.g a cell) due to its construction, which caused a loss in energy/voltage as the charge passes through the source.
Add internal resistance pag stuff here.
What is the work function of a metal?
The work function of a metal is the minimum amount of energy a photon must have to cause an electron to be released from the metal’s surface.
State the principle of superposition of waves.
When two waves meet at a point, the resultant displacement at that point is equal to the sum of the displacements of the two individual waves.
How to work out the uncertainty of a gradient of a graph?
Draw a line of worst fit and compare
