1 The diagram shows an electrical circuit with wires and switches and with five components, labelled A, B, C, D and E.
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\includegraphics[max width=\textwidth, alt={}, center]{11c2d98f-1f72-4f1b-b971-5521bee09358-2_261_519_621_1224}

1. Draw a graph showing which vertices are connected together, either directly or indirectly, when the two switches remain open.
2. How many arcs need to be added to your graph when both switches are closed? The graph below shows which components are connected to each other, either directly or indirectly, for a second electrical circuit.
   \includegraphics[max width=\textwidth, alt={}, center]{11c2d98f-1f72-4f1b-b971-5521bee09358-2_410_494_1356_788}
3. Find the minimum number of arcs which need to be deleted to create two disconnected sets of vertices, and write down your two separate sets.
4. Explain why, in the second electrical circuit, it might be possible to split the components into two disconnected sets by cutting fewer wires than the number of arcs which were deleted in part (iii).