Energy Transfers in Devices: A diagram showing how different forms of energy are converted in common devices, including battery-powered torch, kettle, microphone, and pendulum.

Let’s go step by step to fill in the missing energy types for each device.

We are given a list of energy types to choose from:
Chemical potential, Kinetic, Elastic potential, Electrical, Gravitational potential, Light, Thermal, Sound

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1. Battery powered torch

- Energy in: Chemical potential (already filled) → batteries store chemical energy
- Device: Battery powered torch
- Energy out: The torch gives off Light and also some Thermal (it gets warm), but since only one box is shown and light is the main purpose, we’ll put Light.
→ But wait — looking at the diagram, it says “Energy out” as one box. In many school diagrams, they expect the *main useful output*. For a torch, that’s Light. However, sometimes they accept both — but since only one box, let’s check context.

Actually, looking again — in the kettle example, thermal is listed as output, which is correct. For torch, light is primary. So:

✔ Energy out = Light

*(Note: Some curricula might say “Light and Thermal”, but since only one box, and light is intended output, we go with Light.)*

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2. Kettle

- Energy in: ? → Kettles plug into mains or use electricity → so Electrical
- Device: Kettle
- Energy out: Thermal (already filled) → heats water

✔ Energy in = Electrical

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3. Microphone

- Energy in: ? → Microphones pick up sound waves → so input is Sound
- Device: Microphone
- Energy out: ? → Converts sound into electrical signal → so Electrical

✔ Energy in = Sound
✔ Energy out = Electrical

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4. Pendulum

- Energy in: ? → A pendulum swings due to gravity. When you lift it, you give it gravitational potential energy. As it swings, it converts to kinetic and back.
But what is the “input”? Typically, you start it by lifting it → so initial energy input is Gravitational potential
- Device: Pendulum
- Energy out: ? → It doesn’t really “output” energy to do work — it just oscillates. But in terms of energy transfer during motion, it constantly swaps between gravitational potential and kinetic. Since the question asks for “energy out”, and pendulums eventually stop due to air resistance/friction → energy is lost as Thermal (and maybe sound). But again, if we think of the main energy form involved in its motion, perhaps they want the conversion happening.

Wait — look at the pattern:

For torch: chemical → light
For kettle: electrical → thermal
For microphone: sound → electrical

So for pendulum: likely they want the energy transformation during swing.

When pendulum is at highest point → gravitational potential
At lowest point → kinetic
So overall, it’s converting between those two.

But the diagram has “Energy in” and “Energy out”. If we consider starting the pendulum, you give it gravitational potential. Then as it moves, it outputs kinetic? Or maybe they consider the continuous transfer.

Actually, in many KS3/4 contexts, for a pendulum, they say:

Input: Gravitational potential (when lifted)
Output: Kinetic (as it swings down) — but then it goes back up...

Alternatively, since it loses energy over time, output could be thermal/sound.

But let’s think simply: the main energy transfer in a swinging pendulum is between gravitational potential and kinetic. Since the diagram shows one input and one output, perhaps they want:

Energy in: Gravitational potential
Energy out: Kinetic

That makes sense for the downward swing.

Some sources say: “A pendulum transfers gravitational potential energy to kinetic energy and back.”

Since the box is singular, and kinetic is the energy of motion, which is what it gains as it falls, I think:

✔ Energy in = Gravitational potential
✔ Energy out = Kinetic

*(Note: In reality, it’s a cycle, but for this level, this is acceptable.)*

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Now let’s compile all answers:

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Battery powered torch
Energy in: Chemical potential
Device: Battery powered torch
Energy out: Light

Kettle
Energy in: Electrical
Device: Kettle
Energy out: Thermal

Microphone
Energy in: Sound
Device: Microphone
Energy out: Electrical

Pendulum
Energy in: Gravitational potential
Device: Pendulum
Energy out: Kinetic

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Final Answer:

Battery powered torch → Energy out: Light
Kettle → Energy in: Electrical
Microphone → Energy in: Sound, Energy out: Electrical
Pendulum → Energy in: Gravitational potential, Energy out: Kinetic