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

Answers ( 3 )

  1. herbert hall
    herbert hall
    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. lola duval
    lola duval
    (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. dylan martin
    dylan martin
    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)          
                              

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