Lead(II) bromide, PbBr₂, is electrolysed using inert electrodes as shown (molten, heated, with a bulb in the circuit).

1. aWhat happens to the brightness of the bulb when heating is stopped? Give a reason for your answer. [3]
2. bSuggest another substance that can be used instead of lead(II) bromide to cause the flow of current. [1]

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