VII. Arrange in increasing order of unit.

Question 1.

1 Metre, 1 centimetre, 1 kilometre, and 1 millimetre.

Answer:

1 millimetre < 1 centimetre < 1 Metre < 1 kilometre.

VIII. Find the answer for the following questions within the grid.

- 10
^{-3}is one _____ - SI Unit of time _____
- Cross view of reading for a measurement leads to _____
- _____ is the one what a clock reads.
- _____ is the amount of substance present in an object
- _____ can be taken to get the final reading of the recordings of different of students for a single measurement.
- _____ is a fundamental quantity.
- _____ shows the distance covered by an automobile.
- A tailor use _____ to take measurements to stitch a cloth.
- Liquids are measured with this physical quantity.

- Millimetre
- second
- error
- Time
- Mass
- Average
- Length
- Odometer
- Tape
- Litre

Question 1.

What is the full form of SI system?

Answer:

An international system of unit

Question 2.

Name any one instrument used for measuring mass.

Answer:

Beam balance.

Question 3.

Find the odd one out: Kilogram, millimetre, centimetre, nanometre.

Answer:

Kilogram

Question 4.

What is the SI Unit of mass?

Answer:

Kilogram.

Question 5.

What are the two parts present in a measurement?

Answer:

- multiple
- sub

Question 1.

Define measurement.

Answer:

The comparison of an unknown quantity with some known quantity is known as measurement.

Question 2,

Define mass?

Answer:

Mass is the measure of the amount of matter in an object.

Question 3.

The distance between two places is 43.65 km. Convert it into metre and cm. 0

Answer:

(a) Convert km into metre

1 km = 1000m

∴ 43.65 km = 43.65 × 1000 = 43650.00 = 43650

= 43650 m.

(b) Convert km into cm.

1 km = 1000 m

1 m = 100 cm

1 km = 1000 × 100 cm

1 km = 100000 cm

∴ 43.65 km = 43.65 × 100000 = 4365000.00

= 4365000 cm.

Question 4.

What are the rules to be followed to make an accurate measurement with scale?

Answer:

- To avoid the parallax error.
- Your eye must be exactly in front of vertically above the point where the measurement has to be taken.

XI. Solve the following.

Question 1.

The distance between your school and your house is 2250 m. Express this distance in kilometre.

Answer:

Distance between school and house is 2250 m.

1000 m = 1 km

∴ 2250 m = 2250 ÷ 1000 = 2.25 km.

Question 2.

While measuring the length of a sharpened pencil, reading of the scale at one end is 2.0 cm and at the other end is 12.1 cm. What is the length of the pencil?

Answer:

The difference between the two readings is the length of the pencil.

= 12.1 cm – 2.0 cm

= 10.1 cm or 10 cm and 1 mm.

XII. Write in detail.

Question 1.

Explain two methods those you can use to measure the length of a curved line.

Answer:

Measuring the length of a curved line, by two methods.

First method – using a string.

- Draw a curved line AB on the paper.
- Place a string along the curved line.
- Make sure that the string covers e very bit of the curved line.
- Mark the points where the curved line begins and ends on the string.
- Now stretch the string along the length of a meter scale.
- Measure the distance between two markings of the string.
- This will give the length of a curved line.

- Draw a curved line AB on a paper.
- Separate the legs of the divider by 0.5 cm or 1 cm using a ruler.
- Place it on the curved line starting from one end. Mark the position of the other end.
- Move it along the line again and again cutting the line into number of segments of equal lengths.
- The remaining parts of the line can be measured using a scale.
- Count the number of segments.
- Length of the line = (No. of segments × length of each segment) + length of the left over part.

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