Required Practical 3: Resistance

What is the purpose of this video?

• To describe how to investigate the factors affecting the resistance of electrical circuits

• To explain the concept of resistance in electrical circuits

• To demonstrate how to use a voltmeter and ammeter in a circuit

• To discuss the importance of required practicals in exams

What is the equation used to calculate resistance?

• Resistance (ohms) = Potential difference (volts) / Current (amperes)

• Resistance (ohms) = Current (amperes) / Potential difference (volts)

• Resistance (ohms) = Length of wire (meters) / Current (amperes)

• Resistance (ohms) = Potential difference (volts) * Current (amperes)

What is the purpose of using crocodile clips in the circuit?

• To connect the wire to the rest of the circuit

• To measure the resistance of the wire

• To increase the length of the wire

• To reduce the heating effect in the wire

What does the graph obtained from the experiment show?

• A straight line indicating that resistance is directly proportional to the length of the wire

• A curved line indicating that resistance is inversely proportional to the length of the wire

• A horizontal line indicating that resistance is constant regardless of the length of the wire

• A vertical line indicating that resistance is infinite for all lengths of the wire

What is a zero error in this practical?

• A reading on a measuring instrument when the value should be zero

• A systematic error that can be reduced by taking repeat measurements

• A resistance caused by the contact between the crocodile clip and the wire

• A heating effect that increases the resistance of the wire

How can the heating effect in the wire be reduced?

• By using a low potential difference and turning off the current between readings

• By using a high potential difference and keeping the current constant

• By using a short wire and increasing the current

• By using a thick wire and increasing the potential difference

What is the purpose of a variable resistor in a circuit?

• To control the potential difference across a component

• To measure the current in the circuit

• To increase the resistance of the wire

• To decrease the resistance of the wire

How does increasing the resistance in the circuit affect the lamp?

• It makes the lamp dimmer

• It makes the lamp brighter

• It turns off the lamp

• It has no effect on the lamp

What can be found in the Vision Workbook?

• Plenty of questions on required practicals

• Detailed explanations of electrical circuits

• Step-by-step instructions on using measuring instruments

• Information on the history of electricity

What is the main focus of this video?

• Investigating the factors affecting the resistance of electrical circuits

• Exploring the different types of electrical circuits

• Discussing the importance of practical exams

• Demonstrating how to use a variable resistor