circuit diagram below consists of a battery with 18v, an ammeter, and three resistors of 6,5 and 4 ohms

Question

of varying resistance . Ignore the resistance of the conducting wires and battery.
Figure 7: Electric circuit with a battery, two ammeters and three resistors.
Question 4.1 [2 marks]
Define the term OHM’s LAW in words.
Question 4.2 [4 marks]
Calculate the effective resistance of the circuit.
Question 4.3 [2 marks]
Calculate the current reading on the ammeter.

Answer 1

Question 4.1: Define Ohm’s Law in words.

Ohm's Law states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance of the conductor. This relationship can be expressed mathematically as \( I = \frac{V}{R} \), where \( I \) is the current in amperes, \( V \) is the voltage in volts, and \( R \) is the resistance in ohms.

Question 4.2: Calculate the effective resistance of the circuit.

Assuming that the three resistors (6 ohms, 5 ohms, and 4 ohms) are connected in series, the effective resistance \( R_{total} \) can be calculated by summing the individual resistances:

\[ R_{total} = R_1 + R_2 + R_3 \]

Plugging in the values:

\[ R_{total} = 6, \Omega + 5, \Omega + 4, \Omega = 15, \Omega \]

Question 4.3: Calculate the current reading on the ammeter.

Using Ohm’s Law, we can find the current \( I \) using the total voltage from the battery and the effective resistance calculated in the previous step.

Given:

• Voltage \( V = 18, V \)
• Total Resistance \( R_{total} = 15, \Omega \)

Using the formula \( I = \frac{V}{R} \):

\[ I = \frac{18, V}{15, \Omega} = 1.2, A \]

Thus, the current reading on the ammeter would be 1.2 A.