Magyar Information Contest Journal Articles

# Problem P. 4096. (October 2008)

P. 4096. An object is 20 cm away from a concave mirror, and it is within the focal length of the mirror. If the mirror is changed to a plane mirror the image moves 15 cm closer to the mirror.

a) What is the focal length of the concave mirror?

b) Calculate the enlargement.

(3 pont)

Deadline expired on 11 November 2008.

### Statistics:

 161 students sent a solution. 3 points: 81 students. 2 points: 68 students. 1 point: 9 students. 0 point: 3 students.

 Our web pages are supported by: Morgan Stanley