Where should a stretched wire, held between two fixed supports, be plucked and touched to excite its second harmonic ?

Explanation

To determine where to pluck and touch a stretched wire held between two fixed supports to excite its second harmonic, we can follow these steps:

### Step 1: Understand the concept of harmonics
The second harmonic of a stretched wire corresponds to a standing wave pattern with two loops (antinodes) and one node in the center. The general formula for the harmonics of a string fixed at both ends is given by:
- The first harmonic (fundamental frequency) has 1 loop (1 antinode).
- The second harmonic has 2 loops (2 antinodes).

### Step 2: Visualize the wire and its nodes/antinodes
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