# Measurement of Length Class-6th Goyal Brothers Physics Solutions

Measurement of Length Class-6th Goyal Brothers Physics Solutions Chapter-2, Unit 1. We Provide Step by Step Answers of Objective, True False , Fill in the blanks, Match the following , Study Questions of Chapter- 2 , Physical quantities and measurements ,Unit-1 (Measurement of Length). Visit official Website  for detail information about ICSE Board Class-6.

## Measurement of Length Class-6th Goyal Brothers

Physics Solutions Chapter-2 unit-1

 Board ICSE Class 6th Subject Physics Book Name Goyal Brothers Theme-2 Physical quantities and measurements Unit-1 Measurement of Length Topic Solution of exercise questions Session 2023-24

### OBJECTIVE TYPE QUESTIONS

Physics Solutions Chapter-2, unit-1

#### A. Fill in the blanks :

1. _Length_ is the measure of distance between two points.
2. One kilometre is _thousand_ times the length of one metre.
3. One millimetre is _one-tenth_ part of a centimetre.
4. The SI unit of a length is _metre_.

#### B. Write ‘True’ or ‘False’ for the following statements :

1. One millimetre is equals to one million metres. [F]
2. The distance of stars from the earth is measured in mega-metres. [F]
3. One light year is equal to a distance of 9.46 x 1012Km. [T]
4. A standard unit is a basic unit acceptable to scientists and general public. [T]
5. The magnitude of a standard unit should not change with respect to time and place. [T]

#### C. Statement given below are incorrect. write the correct correct statement:

1. One kilometre is equals to 100 metres.

Correct Statement: One kilometre is equals to 1500 metres.

2. The distance of the planets and stars from earth is measured in millimetres.

Correct Statement: The distance of the planets and stars from earth is measured in light year.

3. The standard unit of length is millimetre.

Correct Statement:The standard unit of length is metre.

4. Metre scale is used to measure the circumference of a cylinder.

Correct Statement: Metre scale is used to measure the heightof a cylinder.

5. A centimetre is 100 times the length of one metre.

Correct Statement: A metre is 100 times the length of one centimetre.

#### 1. The appropriate unit for measuring the thickness of a coin is:

(a) centimetre

(b) millimetre

(c) micrometre

(d) kilometre

Ans: (b) millimetre

#### 2. The appropriate unit for measuring the distance of stars from the earth is :

(a) light year

(b)kilometre

(c) mega-metre

(d) millimetre

Ans: (a) light year

#### 3.  One light year is  :

(a) 9.46 x 1012Km.

(b) 9.64 x 1012Km

(c) 94.6 x 1012Km

(d) 96.4 x 1012Km

Ans: (a) 9.46 x 1012Km.

#### 4. A standard unit should :

(a) be convenient in size

(b) not change with change in place

(c)not change with time

(d) all of these.

Ans: (d) all of these.

#### (e) metre

Column A Column B

### STUDY QUESTIONS

#### Question 1. What is length ? Name four early units of measurement of length.

Answer: Length is the term used for identifying the size of an object or distance from one point to the other.

Four early units of measurement of length are meter, centimeter, millimeter, and kilometer.

#### Question 2. Why do we need standard units for measurement?

Answer: There are mainly two important purposes of using standard units, they are: To measure the quantities accurately. To convey the measurements to other people so that they understand those measurements accurately and follow the same further.

#### Question 3. What are standard international units of measurement? State the unit of length in this system.

Answer: A unit which is acceptable all over the world. The SI unit of length is Metre, symbol m.

#### Question 4. Define the term metre. Name one multiple and two submultiples of metre.

Answer: The meter is defined as the length of the path traveled by light in a vacuum in a second. It is a base unit to measure the distance between two points. One multiple of metere is Kilometre and sub-multiple of metre is centimetre.

#### Question 6. Name two characteristics of a standard unit for a physical quantity.

Answer: Two characteristics of a unit are:-

•  It should be of convenient size
•  It must be universally accepted i.e. its value must remain the same at all places and at all times.

#### Question 7. By using a thin cotton thread , how will you find length of a curved line ?

Answer: For measuring the curved line with a cotton thread, the following steps are followed ;-

• Take a thread and tie a knot at its one end. This knot will act as a starting point for measuring the length of the curved line.
• Place the knot of the thread at a point A on the left end of the curved line with the help of thumb and forefinger.
• Hold the thread a little distance away from the knot and keep it along the curved line with the help of right thumb and forefinger.

In this way, run the thread all along the curved line in little steps at a time, keeping the thread taut, till the other end B of the curved line is reached. Make an ink mark on the thread where it touches the other end B of the curved line. Now, straighten the thread and measure its length between the knot and the ink mark by keeping it along a scale. This will give us the length of  the curved line.

#### Question 10. Name the units for measuring the distance of a star from t he earth. How many kilometres are present in the above unit?

Answer: The appropriate unit for measuring the distance of stars from the earth is light years because of the large magnitude of distance. Its value is equal to 9.46×1012 km.

#### Question 11. Name two units for measuring the diameter of a bacterial cell or nucleus of atom. Express the value of above units in mm.

Answer: Bacterial cells are usually considered to have a diameter of 1 to 2 microns. A micron is one millionth of a meter or 10−6meters.

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