Solution

The figure shows the so-called autotransformer, its feature is that the input and output windings are combined into one.

The essence of the operation of such a transformer is as follows: the input voltage is applied to a fixed section of the winding, let the number of turns on it be N_1. The output voltage is removed between the common wire and terminal K, denote the number of turns between them N_2.

The bottom line is that the output voltage increases proportionally as N_2 increases.:

$$U = \frac{N_2}{N_1} U_0$$

Therefore, when moving the terminals to the left, the output voltage will increase.