Edexcel iGCSE Physics (4PH1) 2.1 Units Exam Style Question Paper 1B - New Syllabus
Questions
This question is about a filament lamp.
(a) Which of these is the correct circuit symbol for a filament lamp?
(b) The filament lamp emits visible light. The table gives some statements about visible light. Place ticks (✓) in the boxes to show which statements are correct for visible light.
(c) The diagram shows a ray of light from the filament lamp incident on the reflective side of a curved mirror.
Complete the diagram by drawing
(i) the normal line where the ray is incident on the mirror.
(ii) the reflected ray of light.
(d) The filament lamp is connected in a circuit with a switch and a battery of three cells.
(i) When the switch is on, the filament lamp transfers \(120\,\mathrm{J}\) of energy in a time of \(3.0\,\mathrm{minutes}\). Each cell has a voltage of \(1.5\,\mathrm{V}\). Calculate the current in the filament lamp.
(ii) A small plotting compass is placed near the wires in the circuit. When the switch is turned on, the compass needle moves to a new position. Give a reason why the compass needle moves.
Syllabus Topic Codes (Edexcel International GCSE Physics 4PH1):
• 3.10–3.12: The Electromagnetic Spectrum and Uses of Electromagnetic Waves — part (b)
• 3.15–3.16: Law of Reflection and Ray Diagrams — part (c)
• 2.4–2.5: Power, Current, Voltage, and Electrical Energy Transfer — part (d)(i)
• 6.8: Electromagnetism — part (d)(ii)
▶️ Answer/Explanation
(a) Filament lamp circuit symbol
The correct symbol is the filament lamp symbol shown in the answer image.
A is incorrect because it is an LED.
C is incorrect because it is a motor.
D is incorrect because it is an LDR.
(b) Visible light
The ticks shown in the answer image identify the statements that correctly describe visible light.
(c) Reflection from a curved mirror
(i) Draw the normal at the point of incidence. The normal must be perpendicular to the mirror surface at that point.
(ii) Draw the reflected ray on the other side of the normal so that:
\(\boxed{\mathrm{angle\ of\ reflection}=\mathrm{angle\ of\ incidence}}\)
(d)(i) Current in the filament lamp
The three cells are connected in series, so the total voltage is:
\(V=3\times1.5=4.5\,\mathrm{V}\)
Convert the time into seconds:
\(t=3.0\times60=180\,\mathrm{s}\)
Use the electrical energy equation:
\(E=IVt\)
Rearranging:
\(I=\dfrac{E}{Vt}\)
\(I=\dfrac{120}{4.5\times180}\)
\(I=0.148\ldots\,\mathrm{A}\)
\(\boxed{I=0.15\,\mathrm{A}}\)
(d)(ii) Effect on the plotting compass
When the switch is turned on, current flows through the wire. A current-carrying conductor produces a magnetic field around it.
The magnetic field interacts with the magnetic field of the compass, causing the compass needle to move.