Page 73 - Physics - XI

7. Now, divide each 1.0 cm interval into fi ve equal divisions on PQ by marking points at every interval of
2 mm. Mark these points up to 15 cm mark.

8. Now, draw sharp small lines about 3 mm long perpendicular to PQ on each of the point which is
separated by 2 mm.

9. Draw another line AB parallel to PQ at a gap of 3 mm.
10. Darken each line and division by the sharp black pen and write 1, 2, _____ 15 at each cm mark.

11. Cut the rectangular scale by a sharp paper cutter and paste it on a thick ivory sheet and cut the sheet
along the boundary of the rectangle with the help of scissors.

12. Paper scale of least count 0.2 cm and of the range of 15 cm is ready.

B. Procedure of making Paper scale of least count 0.5 cm
1. Repeat the steps 1 to 6 of part A.

2. Divide each 1.0 cm interval into two equal divisions on PQ by marking points at every interval of 5 mm
and mark these points up to 15 cm mark. (Fig. 1.2)
3. Draw sharp small lines about 3 mm long perpendicular to PQ on each of the point which is separated
by 5 mm.

4. Draw another line AB parallel to PQ at a gap of 3 mm.
5. Darken each line and division by the sharp black pen and write 1, 2, _____ 15 at each cm mark.
6. Repeat step 11 of part A.

7. Paper scale of least count 0.5 cm and of the range of 15 cm is ready.
C. Measure the length of pencil with the paper scale

1. Place one end of the pencil along the scale (A) in such a way so that the end at the pencil lies at full
mark say 1 cm and read the position of the other end. Repeat the observation by placing the one end of
the pencil at 2 cm mark and take the reading of the other end.
2. Use the second scale (B) of least count 0.5 cm in the similar manner as explained in step 1 and record
the observations.

Observations
Scale A

Least count of the scale (A) = 0.2 cm

Table for calculation of length of the pencil using scale (A)

S. Reading at one end of the Reading at other end Length of the pencil = a – a 1
2
No. pencil a (cm) a (cm) (cm)
1 2
1. 1.0

2. 2.0

Mean length of the pencil = _____ cm

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