1. 1
   An electronics technician connects a 6 Ω resistor to a battery. The current flowing through the resistor is measured to be 2 A.

   (a)

   Which equation should the technician use to calculate the voltage across the resistor?

   [1 mark]

   • AV = I × R
   • BV = I ÷ R
   • CV = I + R
   • DV = R ÷ I

   (b)

   Which statement best describes electric current in the metallic resistor wire?

   [1 mark]

   • AA flow of positively charged ions
   • BA flow of negatively charged electrons
   • CA flow of neutral atoms
   • DA flow of protons through the metal

   (c)

   Calculate the voltage across the resistor.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A mobile phone is charged using a charger that delivers a constant current of 1.5 A for 3000 s at a voltage of 5 V.

   (a)

   Which equation should be used to calculate the total charge delivered to the phone battery during charging?

   [1 mark]

   • AQ = I + t
   • BQ = I ÷ t
   • CQ = I × t
   • DQ = t ÷ I

   (b)

   Which equation should be used to calculate the energy transferred to the battery once the total charge delivered is known?

   [1 mark]

   • AE = Q × V
   • BE = Q ÷ V
   • CE = Q + V
   • DE = V ÷ Q

   (c)

   Calculate the total charge delivered to the battery during the 3000 s charging period.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   In a laboratory circuit, two resistors of 4 Ω and 8 Ω are connected in series with a 12 V battery. Elsewhere in the laboratory, a student observes a separate junction in a circuit where a current of 3 A flows in and splits into two branches, one of which carries 1.2 A.

   (a)

   Calculate the current flowing through the two resistors in the series circuit.

   [3 marks]

   (b)

   Using the idea that current is conserved at a junction, calculate the current in the second branch at the junction. Then calculate the voltage across the 8 Ω resistor in the series circuit.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   An engineer is designing a low-voltage garden lighting circuit. She first measures that a charge of 240 C passes through a lamp when 480 J of energy is transferred to it. Later, when connected to a 15 V supply, the same lamp is found to carry a current of 0.8 A.

   (a)

   Explain what is meant by voltage in terms of energy transferred per unit charge, and use this idea to calculate the voltage across the lamp when 480 J of energy is transferred as 240 C of charge passes through it.

   [6 marks]

   (b)

   Calculate the resistance of the lamp when it is connected to the 15 V supply, and explain what would happen to the current through the lamp if the supply voltage were increased while its resistance stayed the same.

   [6 marks]

   Total for question 4: 12 marks

End of questions