Predict the direction of induced current in the situations described by the following Figs. 6.18(a) to (f ).

 Arrange the object pin O, the lens L and the image pin I on an optical bench or a 

table top as shown in Figure 2 below. Adjust the heights of the object pin O and the 

image pin I so that the tips of O and I lie on the principal axis of the lens.

(ii) Place the object pin O at the 0 cm mark and the lens L at the 30·0 cm mark, so that 

the object distance u = 30·0 cm (i.e. the distance between the lens and the object pin).

(iii) Look at the tip of the object pin O through the lens from a distance so that you see 

an inverted image (say Iʹ) of the object pin.

(iv) Now, adjust the position of the image pin I in such a way, that there is no parallax

between I and Iʹ. Ensure that tip to tip parallax is removed.

(v) At no parallax, note the position of the image pin I and measure the image distance 

v = LI (i.e. the distance between the lens and the image pin) in cm, correct up to 

one decimal place.

(vi) Repeat the experiment for four more values of u, i.e. u =40·0 cm, 50·0 cm, 60·0 cm 

and 70·0 cm. 

(vii) For each value of u, calculate m = v/u and f = 

𝑣

𝑚+1

up to three significant figures.

(viii) Tabulate all five sets of u, v, m and f with their units (if any).

(ix) Show the image position when the parallax has been removed, in any one of the 

readings in (viii) above, to the Visiting Examiner.

(x) Find F, the average of all the five values of f from the observation table and record 

its value with proper units. Write your answer up to one decimal place.