Answer:
h = 10 cm
Step-by-step explanation:
The magnification produced by a mirror is given by :
![m=(h')/(h)](https://img.qammunity.org/2021/formulas/physics/college/qcpmjxez3cnnb1786ln7jw4dz0ejnpa1ik.png)
h' is the image size and h is the object size
We have, h = 10 cm, m = +1
So,
![m=(h')/(h)\\\\h=(10)/(1)\\\\h=10\ cm](https://img.qammunity.org/2021/formulas/physics/high-school/fm3gqand4ijz1fqv8v85nv1tmm1yhs0a8v.png)
So, the size off the object is same as that of the size of the image i.e. 10 cm.