Answer:
a) o = -0.136 m , b) h = 0.643 m
Explanation:
For this problem we will use the constructor equation
1 / f = 1 / o + 1 / i
Where f is the focal length, "o and i" are the distance to the object and the image, respectively
1 / o = 1 / f - 1 / i
1 / o = -1 / 0.300 - 1 / 0.250
1 / o = -7.33
o = -0.136 m
The magnification is given by the expression, we must be careful with the signs
m = h’/ h = - i / o
h = - h ’o / i
h = - 0.350 0.250 / (- 0.136)
h = 0.643 m