Electric Field and Electric Current (Topic 5.1-5.2)

Charge flows through a liquid. The charge flow is made up of positive and negative ions. In one second 0.10C of negative ions flow in one direction and 0.10C of positive ions flow in the opposite direction.

What is the magnitude of the electric current flowing through the liquid?

M19/4/PHYSI/SPM/ENG/TZ1/XX no. 22

• 0 A

• 0.05 A

• 0.10 A

• 0.20 A

The resistance of component X decreases when the intensity of light incident on it increases. X is connected in series with a cell of negligible internal resistance and a resistor of fixed resistance. The ammeter and voltmeter are ideal.

What is the change in the reading on the ammeter and the change in the reading on the voltmeter when the light incident on X is increased?

M19/4/PHYSI/SPM/ENG/TZ2/XX no. 19

• A - increases; V - decreases

• A - increases; V - increases

• A - decreases; V - decreases

• A - decreases; V - increases

Three resistors of resistance 1.0Ω, 6.0Ω and 6.0Ω are connected as shown. The voltmeter is ideal and the cell has an emf of 12V with negligible internal resistance.

What is the reading on the voltmeter?

M19/4/PHYSI/SPM/ENG/TZ2/XX no. 12

• 3.0 V

• 4.0 V

• 8.0 V

• 9.0 V

Three resistors are connected as shown. What is the value of the total resistance between X and Y?

M18/4/PHYSI/SPM/ENG/TZ1/XX no. 18

• 1.5 Ω

• 1.9 Ω

• 6.0 Ω

• 8.0 Ω

Five resistors of equal resistance are connected to a cell as shown.

What is correct about the power dissipated in the resistors?

M18/4/PHYSI/SPM/ENG/TZ1/XX no. 20

• The power dissipated is greatest in resistor X.

• The power dissipated is greatest in resistor Y.

• The power dissipated is greatest in resistor Z.

• The power dissipated is the same in all resistors.

The graph shows the variation of current with potential difference for a filament lamp.

What is the resistance of the filament when the potential difference across it is 6.0V?

M17/4/PHYSI/SPM/ENG/TZ1/XX no. 18

• 0.5 mΩ

• 1.5 mΩ

• 670 Ω

• 2000 Ω

An electron is accelerated through a potential difference of 2.5 MV. What is the change in kinetic energy of the electron?

M17/4/PHYSI/SPM/ENG/TZ1/XX no. 19

• 0.4 µJ

• 0.4 nJ

• 0.4 pJ

• 0.4 fJ

A cell is connected in series with a resistor and supplies a current of 4.0 A for a time of 500s. During this time, 1.5 kJ of energy is dissipated in the cell and 2.5 kJ of energy is dissipated in the resistor.

What is the emf of the cell?

M17/4/PHYSI/SPM/ENG/TZ1/XX no. 20

• 0.50 V

• 0.75 V

• 1.5 V

• 2.0 V

The diagram shows two equal and opposite charges that are fixed in place.

At which points is the net electric field directed to the right?

M17/4/PHYSI/SPM/ENG/TZ2/XX no. 18

• X and Y only

• Z and Y only

• X and Z only

• X, Y and Z

A wire has variable cross-sectional area. The cross-sectional area at Y is double that at X.

At X, the current in the wire is I and the electron drift speed is v. What is the current and the electron drift speed at Y?

M17/4/PHYSI/SPM/ENG/TZ2/XX no. 19

• I and V

• I and  $\frac{v}{2}$  

• 2I and v

• 2I and  $\frac{v}{2}$