Question 1: The IV characteristic of a component describes how the current flowing through it varies with the voltage across it. For resistors, the relationship is linear, following Ohm's Law. For diodes, the relationship is non-linear, with current increasing rapidly after a certain voltage.

Answer: The IV characteristic shows how current varies with voltage; resistors have a linear relationship obeying Ohm's Law, while diodes have a non-linear relationship with a threshold voltage.

Question 1: Define 'Ohm's Law' and state its mathematical expression.

Answer: Ohm's Law states that the current through a resistor is directly proportional to the voltage across it, expressed as V = IR.

Question 2: Explain why the IV characteristic of a diode is non-linear compared to that of a resistor.

Answer: Because a diode only allows significant current to flow after its threshold voltage is reached, resulting in a non-linear relationship.

Question 1: A resistor of resistance 50 Ω has a voltage of 10 V applied across it. Calculate the current flowing through it using Ohm's Law. Show your working.

Answer: I = V / R = 10 V / 50 Ω = 0.2 A

Question 2: A diode has a forward voltage of 0.7 V. If a current of 20 mA flows through it, what is the approximate resistance of the diode in this region? Show your working.

Answer: R = V / I = 0.7 V / 0.02 A = 35 Ω

Question 1: Describe a basic experimental setup to measure the IV characteristic of a resistor. Include the variables you would control and measure, and mention any safety precautions.

Answer: Use a variable power supply, ammeter, voltmeter, and resistor. Control the voltage applied, measure current and voltage at each setting, and gradually increase voltage while monitoring. Ensure connections are secure, avoid short circuits, and handle the power supply carefully.

Question 1: A resistor shows a current of 0.1 A when a voltage of 5 V is applied, and a current of 0.2 A when 10 V is applied. Analyse whether this resistor obeys Ohm's Law, and explain your reasoning.

Answer: Yes, because the ratio V/I remains constant (V/I = 50 Ω in both cases), indicating a linear relationship consistent with Ohm's Law.

Question 1: Explain how the IV characteristic curve of a diode differs from that of a resistor, and discuss its significance in electronic circuits. (6 marks)

Answer: The IV curve of a resistor is linear, showing a proportional increase in current with voltage, indicating ohmic behaviour. In contrast, a diode's IV curve is non-linear, with negligible current until the forward voltage reaches about 0.6-0.7 V, after which current rises rapidly. This behaviour is crucial in rectification and switching applications, allowing current flow in one direction while blocking it in the reverse.

Question 1: Describe how understanding IV characteristics of LEDs (Light Emitting Diodes) helps in designing efficient lighting systems. Include considerations of voltage and current.

Answer: Knowing the IV characteristics of LEDs helps in selecting appropriate voltage and current levels to ensure brightness without damaging the diode. Proper current limiting (via resistors) extends LED lifespan and ensures energy efficiency in lighting systems.