Answer: A. 12inches
Step-by-step explanation:
One of the characteristics of an object placed in front of a plane mirror is that the object distance(u) is equal to the image distance(v) no matter the position of the object from the mirror.
Since object distance is 30 inches, the image distance will be 30inches as will i.e u = v
Using the relationship to get the height of the image
v/u = h1/h0
Where h1 is image height and h0 is object height.
h0 = 12inches
Substituting the values given in the formula we have
30/30 = h1/12
h1 = 12inches.
This means that the image produce by the object is also 12inches tall.