Question

intermediate

1. hafiz is investigating the potential difference across a bulb. he sets up the following circuit, x.

(image of circuit x: a circuit diagram with a battery, ammeter (a), bulb, voltmeter (v), and switch)
(a) name the components in circuit x.
valtwefer
2
(b) hafiz closes the switch in circuit x and observes that the bulb does not light up. his classmate tells him that he has connected one of the components wrongly.
(i) identify the component that hafiz has connected wrongly.
1
(ii) in the space below, draw the circuit diagram for the correct circuit, y, that hafiz should use.

Explanation:

Part (a)

To identify the components in Circuit X, we analyze the symbols: the battery (or cell) provides voltage, the ammeter (A) measures current, the voltmeter (V) measures potential difference, the bulb (light - emitting component), and the switch controls the circuit.

Step 1: Identify each component

• The symbol with two parallel lines (longer and shorter) is a battery (or cell) (provides electrical energy).
• The symbol with "A" is an ammeter (measures electric current).
• The symbol with "V" is a voltmeter (measures potential difference).
• The symbol with the cross - like shape is a bulb (or lamp) (load, emits light when current passes).
• The symbol with the open/close mechanism is a switch (controls the flow of current).

In a correct circuit, a voltmeter is connected in parallel across the component (the bulb, in this case) to measure the potential difference across it. In Circuit X, the voltmeter is connected in series. Since a voltmeter has a very high resistance, connecting it in series will prevent (or drastically reduce) the current from flowing through the circuit, which is why the bulb does not light up. So the wrongly connected component is the voltmeter.

To draw the correct circuit (Circuit Y):

1. The battery (cell) should be connected to the ammeter, then to the bulb, then to the switch, and back to the battery (forming a series path for the current: battery → ammeter → bulb → switch → battery).
2. The voltmeter should be connected in parallel across the bulb. So we draw the battery, ammeter, bulb, and switch in series. Then we connect the two terminals of the voltmeter across the bulb (one terminal to the point before the bulb and one to the point after the bulb in the series circuit).

The circuit diagram (description of the drawing):

• Draw a battery (cell) with the positive terminal connected to the ammeter (A).
• The ammeter is connected to one terminal of the bulb.
• The other terminal of the bulb is connected to one terminal of the switch.
• The other terminal of the switch is connected back to the negative terminal of the battery (this is the series path: battery - ammeter - bulb - switch - battery).
• Now, connect the voltmeter (V) in parallel across the bulb: one terminal of the voltmeter to the terminal of the bulb connected to the ammeter, and the other terminal of the voltmeter to the terminal of the bulb connected to the switch.

(If we were to draw it using standard circuit symbols:

+---[A]---[bulb]---[switch]---+
|                             |
|           [V]               |
+-----------------------------+
  (battery)

Where the battery is represented by the two parallel lines, [A] is the ammeter, [bulb] is the bulb symbol, [switch] is the switch symbol, and [V] is the voltmeter connected across the bulb.)

Answer:

The components in Circuit X are battery (cell), ammeter (A), voltmeter (V), bulb (lamp), and switch.

Part (b)(i)