In an experiment to determine the focal length (f) of a concave mirror by the u−v method, a student places the object pin A on the principal axis at a distance x from the pole P. The image is inverted. The student then moves towards the pole of the mirror and observes that the image of the object is now erect. Which of the following could be true about x?

There are typically three types of mirrors utilised. Convex, concave, and plain mirrors are all available. They will all have various functions. Various mirrors have different characteristics. Convex mirrors constantly create virtual pictures when used as mirrors. While plain mirrors just provide imaginary pictures while concave mirrors create genuine images. In the sense that it is genuine, an inverted image.
We can create different pictures by positioning an object in front of a concave lens in different ways. An image will form on the other side of the concave mirror if anything is positioned between the pole and focus. The picture that is created might be virtual, magnified, or both.

Now, if we position an item between the focus and the centre, the picture will be genuine and inverted since the image is produced away from the centre. According to the diagram, the picture will be larger than the item.
F is the focus, C is the centre, and P is the pole.
The picture that results from moving the item from the centre will fall between the focus and the centre. This picture will be accurate, upside-down, and dimmer.
Given that the picture is inverted and that if the item is moved left, the image moves right, it must have been positioned between the centre and the focus. Only this scenario will thereafter be viable.

Hence, the correct answer is option B.