**Samacheer Kalvi Class 7 Science Term 1 Unit 1 Measurement Solutions**

**Samacheer Kalvi Class 7 Science Term 1 Unit 1 Measurement Solutions**

Welcome to NCTB Solutions. Here with this post we are going to help 7th class students by providing Solutions for Samacheer Kalvi Class 7 Science Term 1 Unit 1 Measurement. Here students can easily find all the solutions for Measurement Exercise questions. Also here our Expert Science Teacher’s solved all the questions with easily understandable language with proper guidance so that all the students can understand easily. Here on this post students will get Unit 1 exercise solutions. Here all the solutions are based on Tamil Nadu State Board latest syllabus.

**Unit 1 Measurement Exercise Questions Solutions :**

**Unit 1 Measurement Exercise Questions Solutions :**

**(I) Choose the best answer.**

**(1) Which of the following is a derived quantity?**

**(a) mass**

**(b) time**

**(c) area**

**(d) length**

**Answer : **

Correct option – (c)

Area is a derived quantity.

**(2) SI unit of density is** ___

**(a) kg/m2**

**(b) kg/m3**

**(c) kg/m**

**(d) g/m3**

**Answer : **

Correct option is – (b)

SI unit of density is kg/m3

**(4) Two spheres have mass and volume in the ratio 2:1. The ratio of their density is**

**(a) 1 : 2**

**(b) 2 : 1**

**(c) 4 : 1**

**(d) 1 : 4**

**Answer : **

The correct option is – (b)

The ratio of their density is 2 : 1

**(5) Light year is the unit of**

**(a) distance**

**(b) time**

**(c) density**

**(d) Both length and time**

**Answer : **

Appropriate option is – (a)

Light year is the unit of Distance.

**(II) Fill in the blanks.**

**(1) Volume of irregularly shaped objects are measured using the law of** ____.

**(2) One cubic metre is equal to** ____** cubic centimetre.**

**(3) Density of mercury is** ____.

**(4) One astronomical unitis equal to** ____.

**(5) The area of a leaf can be measured using a** ____.

**Answer : **

(1) → Archimedes

(2) → 10,00,000

(3) → 13,600 kg/m3

(4) → 1.496 × 10^11m

(5) → Sheet

**(III) State true or false. If false, correct the statement.**

**(1) The region covered by the boundary of a plane figure is called its volume.**

**(2) Volume of liquids can be found using measuring containers.**

**(3) Water is denser than kerosene.**

**(4) A ball of iron floats in mercury.**

**(5) A substance which contains less number of molecules per unit volume is said to be denser.**

**Answer : **

(1) → False

(2) → True

(3) → True

(4) → True

(5) → False

**(V) Arrange the following in correct sequence.**

**(1) 1L, 100 cc, 10 L, 10 cc**

**Answer : **10 cc, 100 cc, 1 L, 10 L

**(VI) Use the analogy to fill in the blank**

**(1) Area : m2 :: Volume :** ____

**(2) Liquid : Litre :: Solid :** ____

**Answer : **

(1) Area : M^2 : : Volume : M^3

(2) Liquid : Litre : : Solid : cm^3

**(VII) Consider the following statements and choose the correct option.**

**(a) Both assertion and reason are true and reason is the correct explanation of assertion.**

**(b) Both assertion and reason are true, but reason is not the correct explanation of assertion.**

**(c) Assertion is true but reason is false.**

**(d) Assertion is false but reason is true**

**(1) Assertion : Volume of a stone is found using a measuring cylinder.**

**Reason : Stone is an irregularly shaped object.**

**Answer : **

The correct option is – (a)

Both assertion and reason are true and reason is the correct explanation of assertion.

**(2) Assertion : Wood floats in water.**

**Reason : Water is a transparent liquid.**

**Answer : **

The answer is option – (b)

Both assertion and reason are true, but reason is not the correct explanation of assertion.

**(3) Assertion : Iron ball sinks in water.**

**Reason: Water is denser than iron.**

**Answer : **

The correct option is – (b)

Both assertion and reason are true, but reason is not the correct explanation of assertion.

**(VIII) Answer very briefly.**

**(1) Name some of the derived quantities.**

**Answer : **

Some of the derived quantities is Area, Volume, Density, Speed.

**(2) Give the value of one light year.**

**Answer : **

One light year = 9.46 x 10^15m

**(3) Write down the formula used to find the volume of a cylinder.**

**Answer : **

We know that, Volume of a cylinder = πr^2 h

**(4) Give the formula to find the density of objects.**

**Answer : **

We know that,

Density (D) = mass (m)/volume (V)

D = m/v

**(5) Name the liquid in which iron ball sinks.**

**Answer : **

Water is the liquid in which iron ball sinks because of higher density of iron ball

**(7) What is the density of gold?**

**Answer : **

We know that,

Density of gold is 19,300 kg/m^3

**(IX) Answer briefly.**

**(1) What are derived quantities?**

**Answer : **

Derives quantities are those physical quantities which are expressed in terms of fundamental quantities.

**(2) Distinguish between the volume of liquid and capacity of a container.**

**Answer : **

**Volume of liquid : **

- It is a place of a body in space.
- The amount of space an object occupies
- It is measure in cubic units

**Capacity of a container : **

- Are objects in which we can make other objects or substance.
- Not every object has capacity
- It is measure in cc or ml

**(3) Define the density of objects.**

**Answer : **

It is defined as the mass of the substance contained in unit volume

D = m/v

**(4) What is one light year?**

**Answer : **

It is the distance travelled by light in vacuum during the period of one year.

1 Light year = 9.46 x 10^15m.

**(5) Define – Astronomical unit.**

**Answer : **

One astronomical unit is the average distance between the sun and the earth.

= 1 AU = 1.496 5 10^6km

= 1.496 × 10^11m.

**(X) Answer in detail.**

**(1) Describe the graphical method to find the area of an irregularly shaped plane figure.**

**Answer : **

We know that we have to use graph paper to find the area of ab irregularly shaped plane figure. The following steps are the procedure:

(a) At first, place a piece of with an irregular shape on a graph paper and draw its outline.

(b) Now, count the number of whole squares enclosed within the outline of the leaf. Than, take it to be M.

(c) Find that some squares lie partially inside the outline.

(d) After that, count the number of squares which are half of a whole square.

(e) Finally, in the last step count the number of squares, that are less than half.

**(2) How will you determine the density of a stone using a measuring jar?**

**Answer : **

With the help of measuring cylinder we can determine the density of a stone using a measuring jar. The steps are the procedure:

(a) Before we start to determine the density we must find the mass and volume of the stone.

(b) Then, take the mass ‘m’ grams and it determined by a physical balance very accurately.

(c) After that, take a measuring cylinder to find the volume and pour in it some water.

(d) Now, record the volume of water with help of marked on measuring cylinder.

(e) Then, first tie the stone to a thread and lower it gently in the measuring cylinder, such that it is completely immersed in water.

(f) Finally, record the new level of water and calculate with the help of density formula which is D = m/v

**(XII) Numerical problems :**

**(1) A circular disc has a radius 10 cm. Find the area of the disc in m2 (Use π = 3.14).**

**Answer : **

In this question we have,

Radius= 10cm

= 0.1m

π = 3.14

Now, we have to find the area of circular disc A

Area of circle = πr^2

= 3.14 × 0.1 × 0.1

= 0.0314m2

**(2) The dimension of a school playground is 800 m × 500 m. Find the area of the ground.**

**Answer : **

In this question we have

Dimension of playground= 800m x 500m

= length x breadth

Now, we have to find the area of playground

Area of the ground A = l x b

= 800 x 500

= 4,00,000m^2

**(3) Two spheres of same size are made from copper and iron respectively. Find the ratio between their masses (Density of copper is 8,900 kg/m3 and iron is 7,800 kg/m3).**

**Answer : **

In this question we have

Density of copper = 8,900 kg/m^3

Density of iron = 7800kg/m^3

We know that the Volume will be same both of the cases

Let take the masses be m

mC = masses of copper

mI = masses of iron

Now, we have to find the ratio

m = D x V

So, mC = mI

= 8900 V = 7800 V

= 1.14 : 1

**(4) A liquid having a mass of 250 g fills a space of 1000 cc. Find the density of the liquid.**

**Answer : **

In this we question we have

Mass of liquid = 250g

V = 1000cc

Now, we have to find density of the liquid

D = M/V

= 250/1000

= 0.25g/cc

**(5) A sphere of radius 1cm is made from silver. If the mass of the sphere is 33g, find the density of silver (Take π = 3.14).**

**Answer : **

In this question we have,

r = 1cm

m = 33g

v = 4/3πr^3

= 4/3 x 3.14 x 1

= 4.187cm^3

Now, we have to find density

D = M /V

= 33 / 4.187

= 7.881g/cc

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