Our teacher has told us that we will being doing an electricity practical task where the notion of "y = mx + b" will be used. (i.e. our graph will
have a non-(0,0) intercept). Does anyone have any idea of what this might be? Thanks!Brain&Force - 14-6-2014 at 23:17
Photoelectric effect?
E = hf - φ where E is the maximum kinectic energy of an electron, h is the Planck constant, f is the frequency of incident light, and φ is the work
function of the metal.aga - 15-6-2014 at 03:55
Ohm's Law i think.
a plot of current vs voltage will be a straight line for a 'normal' fixed resistor, and bent or wiggly for a non-ohmic resistor (one that changes
resistance in reponse to voltage or current).
Edit: Seems y = mx + b is just the formula for a straight line graph.
[Edited on 15-6-2014 by aga]smaerd - 15-6-2014 at 13:58
Could be practically anything. Typically electrical phenomena do not follow perfectly linear equations. Exponential, and sinuisoidal/harmonic
equations seem significantly more common. However, for approximation purposes linear type analysis seems possible.
Photo-electric effect would be one of those things that works as B&F stated.
All kinds of sensors can produce a linear region between two variables. One example currently on my mind would be current verses irradiation of PIN
photodiodes.
Realistically though, a professor could ask anything, "Say the flux of a magnetic field of 5T 4 M away from a 20 turn solenoid that has a surface area
of 20cm^2 follows the equation dPsy/dt = 35x + 12, what is the electricpotential across the solenoid?". etc. Probably better off asking the professor.aga - 15-6-2014 at 22:22
the notion of "y = mx + b" will be used. (i.e. our graph will have a non-(0,0) intercept)
If you just mean the algebra part, then it means 'a straight line' if you draw a graph.
y = something times x plus a bit.
If the 'bit' (b) is not zero, then you'll not get a result where x=0 and y=0, i.e. a '0,0 intercept', so long as b is not 0.
That pdf looks like a class handout ...woelen - 15-6-2014 at 22:47
The ohmic law is not a good example of y=mx + b, for b not equal to 0. Every passive resistor, being linear or not has a characteristic, which can be
written as V = R(I), where R is a function of the current I, with the property R(0) = 0. It is not necessarily true that R(-I) = -R(I), e.g. think of
a diode. For a linear resistor, R(I) is of the form R*I, with * being normal multiplication.aga - 16-6-2014 at 14:21
The ohmic law is not a good example of y=mx + b, for b not equal to 0
Agreed.
The class should be on Ohm's Law and the straight line equation given in a different class.
Combining the two will just confuse the students.PHILOU Zrealone - 17-6-2014 at 09:08
R is also R(T) when temperature increases resistivity also does and when it freezes outside the current encounters less resistance. Artemus Gordon - 17-6-2014 at 19:51
A forward-biased Silicon diode is a good example of y = mx + b. Current flow is negligible until voltage = approx. 0.6v, then it behaves Ohmically
(Resistance = m, current = x, voltage = y).
