Ch11 A-level Physics CIE (flipped)

The resistance that charge experiences as it moves through any power source

internal resistance

The symbol for a cell with internal resistance

The equation that links the voltage measured when a voltmeter is connected over a cell, the emf of the cell, and the 'lost volts'.

V = E - lost volts

the equation that links emf, current, internal resistance and the resistance of the entire external circuit.

E = IR + Ir

The circuit you use to find the internal resistance of a cell

The graph you draw when doing the experiment to find internal resistance

In the internal resistance experiment graph, the Y-INTERCEPT equals...

emf

In the internal resistance experiment graph, the GRADIENT equals...

-r

As the current drawn from a cell increases, the pd measured across its terminals...

decreases

As the current drawn from a cell increases, the pd measured across its terminals decreases because...

more volts are lost over the internal resistance

The symbol for a potential divider circuit

The symbol for a potentiometer circuit

What is the advantage of using a variable resistor as a potentiometer?

a whole range of voltages can be achieved, from zero to the supply voltage

The potential divider equation

Vout = Vin x R2/(R1+R2)

As the temperature increases, the resistance of a thermistor...

decreases

As the light gets brighter, the resistance of an LDR...

decreases

The name for a very sensitive ammeter

galvanometer

The name for a connector with a sharp edge

jockey

When using a potentiometer circuit to compare emfs, we move the jockey until...

the galvanometer reads zero

When using a potentiometer circuit to compare emfs, when the galvanometer reads zero we say the circuit is...

balanced

When a potentiometer is balanced, the 'lost volts' in the smaller cell are...

zero

The equation for the unknown emf in a potentiometer circuit

Ex = E0 AY/AB

The meaning of 'Ex' in the equation for the potentiometer circuit

unknown emf

The meaning of 'E0' in the equation for the potentiometer circuit

known emf

The meaning of 'AB' in the equation for the potentiometer circuit

total length of the potentiometer wire

The meaning of 'AY' in the equation for the potentiometer circuit

length of potentiometer wire in Ex's circuit