Level 3 internal R

What is emf?

• the electro motive "force" or the force on electrons

• the electromotive "force" or the Voltage of a cell measured when there is no current flowing

• the electromotive "field" or the Voltage of a cell measured when there is no current

• the electromotive "force" or Voltage of a cell measured when connected to a circuit

What is internal resistance?

• the resistance inside the cell that increases with more current drawn from the cell

• the resistance inside the cell that decreases with more current drawn from the cell

• the resistance inside the cell that remains constant as the current drawn from the cell changes

• the resistance inside each component which increases as more resistances are added in series

The relationship above shows that ...

• voltage is positively proportional to current

• voltage is inversely proportional to current

• voltage is negatively proportional to current

• current is inversely proportional to voltage

The gradient of this line represents the

• internal resistance

• emf of the cell

• power of the cell

• resistance of the circuit

The "y" intercept of this graph represents the

• internal resistance

• total resistance

• total voltage

• emf of the cell

Calculate the emf USING THE GRAPH LINE

• 1.53 V

• 1.54 V

• 0V

• 1.47 V

Calculate the internal resistance of the circuit USING THE GRAPH

• 0.1 ohms

• 0.2 ohms

• 2 ohms

• 0.5 ohms

What is the equation for this graph?

• 1.34 = I(0.5) + V

• V = I(2) + 1.34

• V = I(0.5) + 1.35

• V = 1.34 - I(0.5)

When the voltage output is 1.00 V, the current is...

• 1.3 A

• 0.14 A

• 1.08 A

• 0A

A lemon has an emf = 1.0 V and internal resistance of 1000 ohms. What is the total internal resistance when 5 lemons are connected in series and the total emf?

• 5 ohms 5V

• 5000 ohms 1V

• 0.2 ohm 5V

• 2 ohms 1V