Answer:
Explanation:
A converging mirror is also known as a concave mirror. For a concave mirror, its focal length and the image distance are both positive.
Using the mirror formula as shown to get the object distance;
[tex]\frac{1}{f} = \frac{1}{u} + \frac{1}{v}[/tex]
f is the focal length of the mirror
u is the object distance
v is the image distance
Given f = 30cm and v = 2u (The image formed is twice the size of the pencil)
Substituting this values in the formula to get u we have;
[tex]\frac{1}{30} = \frac{1}{u} + \frac{1}{2u}\\\frac{1}{30} = \frac{2+1}{2u}\\\frac{1}{30} = \frac{3}{2u}\\[/tex]
Cross multiplying we have;
2u = 90
Dividing both sides by 2;
2u/2 = 90/2
u = 45cm
The distance of the object from the mirror is 45cm
