Do as directed.
(Conversion of tenses) 1. Rehana is singing a song. (Simple past tense) 2. Mrs. Shah sings very sweetly (Present perfect cont. Tense) 3. He runs on the road. (Simple Past tense) 4. The train is on the road. (Simple Past Tense) 6 5. Radha did not go to school. (Future Perfect) twt
Answers
Answer:
Explanation:
To make a paper scale of given least count: (a) 0.2 cm and (b) 0.5 cm
Thick ivory/drawing sheet; white paper sheet; pencil; sharpener;
eraser; metre scale (ruler); fine tipped black ink or gel pen.
Least count of a measuring instrument is the smallest measurement
that can be made accurately with the given measuring instrument.
A metre scale normally has graduations at 1 mm (or 0.1 cm) spacing,
as the smallest division on its scale. You cannot measure lengths
with this scale with accuracy better than 1mm (or 0.1 cm).
You can make paper scale of least count (a) 0.2 cm (b) 0.5 cm, by
dividing one centimetre length into smaller divisions by a simple
method, without using mm marks.
(a) Making Paper Scale of Least Count 0.2 cm
1. Fold a white paper sheet in the middle along its length.
2. Using a sharp pencil, draw a line AB, of length 30 cm in either
half of the white paper sheet [Fig. A1.1(a)].
3. Starting with the left end marked A as zero,
mark very small dots on the line AB after
every 1.0 cm and write 0,1,2 ..., 30 at
successive dots.
4. Draw thin, sharp straight lines, each 5 cm
in length, perpendicular to the line AB at
the position of each dot mark.
5. Draw 5 thin, sharp lines parallel to the line
AB at distances of 1.0 cm, 2.0 cm, 3.0
cm, 4.0 cm and 5.0 cm respectively. Let
the line at 5 cm be DC while those at 1 cm,
Fig. A1.1(a): Making a paper scale
of least count 0.2 cm
ACTIVITIES
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LABORATORY MANUAL
LABORATORY MANUAL
2 cm, 3 cm, and 4 cm be A1B1, A2B2, A3B3 and A4B4 respectively
[Fig A 1.1(a)].
6. Join point D with the dot at 1 cm on line AB. Intersection of this
line with lines parallel to AB at A4, A3, A2 and A1 are respectively
0.2 cm, 0.4 cm, 0.6 cm and 0.8 cm in length.
7. Use this arrangement to measure length of a pencil or a knitting
needle with least count of 0.2 cm.
(b) Making Paper Scale of Least Count 0.5 cm
1. Using a sharp pencil, draw a line AB of length 30 cm
in the other half of the white paper sheet [Fig. A1.1(b)].
2. Repeat steps 3 to 6 as in the above Activity 1.1(a), but
draw only two lines parallel to AB at distances 1.0 cm
and 2.0 cm instead of 5 cm.
3. Join diagonal 1-D by fine tipped black ink pen [Fig. A
1.1 (b)].
4. Use this scale to measure length of a pencil/knitting needle with
least count of 0.5 cm. Fractional part of length 0.5 cm is measured
on line A1B1.
(c) Measuring the Length of a Pencil Using the Paper Scales A and B
1. Place the pencil PP’ along the length of the paper scale A (least
count 0.2 cm) such that its end P is on a full mark (say 1.0 cm or
2.0 cm etc. mark). The position of the other end P′ is on diagonal
1–D. If P′ goes beyond the diagonal, place it on next upper line, in
which fraction of intersection is 0.2 cm larger, and so on. Thus, in
Fig. A 1.1 (a), length of the pencil = 3 cm + .2 × 2 cm = 3.4 cm. Take
care that you take the reading with one eye closed and the other
eye directly over the required graduation mark. The reading is
likely to be incorrect if the eye is inclined to the graduation mark.
2. Repeat preceding step 1, using the paper scale B having least
count 0.5 cm and record your observation in proper units.
Least count of the paper scale A = 0.2 cm
Least count of the paper scale B = 0.5 cm
1. Rehana sung a song
2. Mrs Shah has been singing very sweetly
3. He ran on the road
4. The train was on the road
5. Radha would have not gone to school