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.