# Transparent photographic slide is placed in front ...

transparent photographic slide is placed in front of a converginglens with a focal length of 2.60 cm.The lens forms an image of the slide 13.5 cm from the slide.
(a) How far is the lens from the slide if theimage is real? (Enter 'none' in the second box if there is only oneanswer.)
 nearer possible distance = cm further possible distance = cm

(b) How far is the lens from the slide if the image is virtual?(Enter 'none' in the second box if there is only one answer.)
 nearer possible distance = cm further possible distance = cm

1. http://www.physicsforums.com/archive/index.php/t-177698.html
Here is the whole question. I got all of aand the second part of b
(a) How far is the lens from the slide if the image is real? (Enter'none' in the second box if there is only one answer.)
nearer possible distance = correct check mark cm
further possible distance = correct check mark cm

(b) How far is the lens from the slide if the image is virtual?(Enter 'none' in the second box if there is only one answer.)
nearer possible distance = wrong check mark cm
further possible distance = correct check mark cm
2. (a)When the image is real,then
(1/f) = (1/s) + (1/s')
Here,f = 2.64cm and s' = 13.3cm
or (1/s) = (1/f) - (1/s')
or (1/s) = (1/2.64) - (1/13.3)
or (1/s) = (10.66/35.112)
or s = (35.112/10.66) = 3.3cm
Therefore,the nearer possible distance is 3.3cm
(b)When the image is virtual,then s' = -13.3cm
Therefore,we get
(1/s) = (1/2.64) - (-1/13.3)
or (1/s) = (1/2.64) + (1/13.3)
or (1/s) = (15.94/35.112)
or s = (35.112/15.94) = 2.02cm
Therefore,the nearer possible distance is 2.02cm.
The further possible distance is none.
3. Given the distance between the slide(object) and image is13.5cm
That is u + v = 13.5cm
v = 13.5 - u
Focal length is f = 2.60cm
We know the lens makers formula is    This is a quadratic equation in u, by solving this quadraticequation we get the value of object distances. b)
Given focal length is f = 2.60cm
The distance between the object and image is 13.5cm
Now image distance is v = u + 13.5
We know the lens makers formula is  Solve similarly like above in thepart(a) 