Physics Question...

El Stevo

see attachment...

my answers...

a) it is the Voltage when the circuit has no IR
b) 2.0A
c) ?
d) ?

Picture.gif.gif30.0KB

Reply 1

username9816

1) The emf of the cell is the intercept of the graph on the voltage axis - This is at V = 1.4V, hence EMF (cell) = 1.4 V.

2.) Extrapolate the graph to the current axis - When V = 0, there is maximum current flowing around the circuit.

3.) Internal resistance = -(Gradient Of Graph)

4.) If the current is allowed to flow for a considerable amount of time, the temperature of the inside of the cell and other components increases and thus this can cause damage to them, so it is inadvisable to let this occur.

Reply 2

El Stevo

sweet... cheers Nima...

Reply 3

username9816

El Stevo

sweet... cheers Nima...

emf = I(R + r)
---> emf = IR + Ir
---> emf = V + Ir
---> V = - Ir + emf
---> V = I(-r) + emf
---> Of Form: y = mx + c

If we draw a graph of V against I (analogous to y against x), then Gradient Of Graph = -r
---> r = -(Gradient Of graph) and the emf is the intercept on the voltage axis.