# Optics problem - 1

1. Feb 7, 2013

Hi friends,

I am sticking in a problem of Geometrical OPTICS,
The problem is as https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-snc6/285225_2890687243573_1306065782_n.jpg

Attempt -

Here for the convex lens applying the lens formula
1/v - 1/u = 1/f

so, 1/v = 1/u + 1/f

1/v = - 1/15 + 1/30 (since I have taken the left side as negative)

after solving this v = - 30 cm.

The image of the object will be 30 cm. far from the lens and left side of the lens and now this image will work as an object for the plane mirror. Its distance from the plane mirror will be 45 cm which is left of the it so it is real as far as I am concerned.

So from the mirror property now its Final image will be 60 cm right of it and will be virtual.

I think that the answer of the question is given wrong cause it is giving the answer options (B) & (C).

Please friends help me in solving this issue.

2. Feb 7, 2013

### ehild

Draw the rays going through the lens and then reflected by the mirror. Do they really intersect in front of the mirror?

ehild

3. Feb 8, 2013