Question

The magnification of a book held 7.40 cm from an 11.1 cm focal length lens was found to be 3.00. (a) Find the magnification for the book when it is held 8.40 cm from the magnifier. (b) Do the same for when it is held 9.40 cm from the magnifler. (c) Comment on the trend in m as the object distance increases as in these two calculations.

Answer 1

a. m =4.112

b. m = 6.529

- The lens formula - do di - di = image distance do = Object distance f = focal length. magnificelicon me Giren f= + 111cm @J do = +8.40 cm. - 34.54 - 1 - This gines 11.1 8.40 I dia - 34.54 cm] virtual maquifecaléon - - 8.40 [m, = 4.112 (b) « - - - t ai to This gives, di = -61.3798 cm.) virtual Jou, Aqави - mis - rece ---61.379 m = 6.529] ~ 653 goh

c. The magnification of the magnifier increases very quickly as the object approaches the focal point, in fact at focal point the magnification is infinity where the formed image is at infinity from right to left.