Question 1:

This is the international symbol for a resistor.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 2:

This is the international symbol for a diode. A light emitting diode (L.E.D.) is similar but has two arrows pointing outwards to symbolize the light being emitted.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 3:

This is the international symbol for a thermistor (a heat dependent resistor). Thermistors (for this GCSE course) will have a lower resistance as the temperature increases.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 4:

Let's check each option:

• A. L.D.R. (Light Dependent Resistor) – changes resistance with light, but does not emit light and can pass current both ways (it’s not directional).

• B. L.E.D. (Light Emitting Diode) – emits light when current flows through it in the forward direction and only allows current in one direction.

• C. Diode – allows current in one direction only, but not all diodes emit light (only LEDs do).

• D. Thermistor – changes resistance with temperature, not directional, and does not emit light.

The question says: “emits light and only lets current pass through one way” — that exactly matches an LED.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 5:

Step 1: Check each option

• A. Resistor – A fixed resistor has a constant resistance, so the V–I graph is a straight line (Ohm's law). Not this shape.

• B. Diode – A diode has very low current for voltage below ~0.6 V, then after that, current rises very steeply – the gradient increases with voltage (not decreases). Not a match.

• C. Bulb (filament lamp) – A filament lamp has resistance that increases with temperature. As current increases, the filament gets hot and resistance increases, so the gradient of an I~V graph decreases.

• D. L.D.R. – Resistance decreases with light; this V–I shape is not characteristic for an LDR without specifying light level, but usually LDR is fixed in light and then V–I is linear. Even varying light, the V–I at fixed light level is linear. Not a match.

The bulb (filament lamp) is the classic example of this curved I–V shape caused by resistance increase with temperature.

Answer: Option C

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 6:

Step 1: Check each option

• A. Resistor – A fixed resistor has a constant resistance, so the V–I graph is a straight line (Ohm's law). Not this shape.

• B. Diode – A diode has very low current for voltage below ~0.6 V, then after that, current rises very steeply – the gradient increases with voltage (not decreases). Not a match.

• C. Bulb (filament lamp) – A filament lamp has resistance that increases with temperature. As current increases, the filament gets hot and resistance increases, so the gradient of an I~V graph decreases.

• D. L.D.R. – Resistance decreases with light; this V–I shape is not characteristic for an LDR without specifying light level, but usually LDR is fixed in light and then V–I is linear. Even varying light, the V–I at fixed light level is linear. Not a match.

So the graph shown matches the characteristics of a diode.

Answer: Option B

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 7:

Let's match each component to its sensing purpose.

• Thermistor – changes resistance with temperature → used for sensing heat.

• LDR – changes resistance with light intensity → used for sensing light.

• LED – emits light, not a light sensor.

So the correct pairing is:
Heat → Thermistor
Light → LDR

That matches option D.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 8:

The correct circuit is B.

To vary the brightness of a bulb using a variable resistor, the components must be arranged correctly according to their circuit symbols and layout:

Component Symbols:

Variable Resistor (Rheostat): Represented by a rectangle with a diagonal arrow passing through it (seen in B and D).

The symbol with a "hockey stick" line (seen in A and C) represents a thermistor, which varies resistance based on temperature, not manual adjustment.

Bulb: Represented by a circle with an 'X' inside.

Circuit Layout:To control the current flowing through the bulb (and thus its brightness), the variable resistor must be connected in series with the bulb.

In Circuit B, the components are in a single loop (series), allowing the variable resistor to change the total resistance and control the bulb's brightness.

In Circuit D, the components are in parallel, which would not effectively control the brightness in the same way.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 9:

When a current flows through any resistor, the resistor opposes the flow of charge, causing collisions between charge carriers and the atoms of the material. This resistance converts electrical energy into heat energy (and sometimes light, as in a bulb, but the fundamental energy transfer for any resistor is heat).

So the correct answer is: A

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 10:

Let’s think through the circuit:

• LDR (light-dependent resistor) and bulb in series

• On a sunny day: More light falls on LDR → LDR’s resistance decreases

• Total resistance in series decreases → total current increases → bulb gets brighter

So:
Sunny → LDR resistance decreases → bulb brighter.

That matches option D.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.