Page 74 - Physics - XI

Scale B
Least count of the scale (B) = 0.5 cm

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

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

Result

1. The scales of the least count 0.2 cm and 0.5 cm have been made.
2. The length of the pencil using scale (A) = _____ cm.

The length of the pencil using scale (B) = _____ cm.

Precautions
1. The cm markings should be longer than 0.2 cm and 0.5 cm markings.

2. Final lines and marking should be drawn by using fi ne tipped black ink pen.
3. Paper scale should be pasted on the thick ivory paper.

4. Use very sharp pencil for the graduation marks.

Sources of Error

1. Graduation marks may not have equal separation.
2. The lines showing graduations may not be sharp as required.

ACTIVITY - 2
Aim

To determine mass of a given body using a metre scale by principle of moments.

Apparatus and Materials Required

A body of unknown mass, a metre Wedge
scale, a broad heavy wedge with
sharp edge, weight box, spirit A G B
level, thread, and a wooden block

a b
Unknown
mass (m) W = Mg
1
W = mg Known
standard
Mass (M)

Fig. 2.1: Determination of mass of a given body using metre scale

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