NCERT Solutions
Class 7 Maths
Exponents and Powers
Electric charges

Ex.13.1 Q.1

Find the value of:

1. 26           

2. 93             

3. 112              

4. 54

View Answer

Ex.13.1 Q.2

Express the following in exponential form:

1. 6 × 6 × 6 × 6

2. t × t  

3. b × b × b × b

4. 5 × 5 × 7 × 7 × 7

5. 2 × 2 × a × a

6. a × a × a × c × c × c × c × d

View Answer

Ex.13.1 Q.3

Express each of the following numbers using exponential notations:

1. 512         

2. 343           

3. 729            

4. 3125

View Answer

Ex.13.1 Q.4

Identify the greater number, wherever possible, in each of the following:

1. 43 and 34      

2. 53 or 35    

3. 28 or 82    

4. 1002 or 2100      

5. 210 or 102

 

View Answer

Ex.13.1 Q.5

Express each of the following as product of powers of their prime factors:

1. 648         

2. 405          

3. 540          

4. 3,600

View Answer

Ex.13.1 Q.6

Simplify:

1. 2 × 103          

2. 72 × 22            

3. 23 × 5           

4. 3 × 44                

5. 0 × 102

6. 52 × 33             

7. 24 × 32      

8. 32 × 104

View Answer

Ex.13.1 Q.7

Simplify:

1. (-4)3         

2. (-3) × (-2)3          

3. (-3)2 × (-5)2          

4. (-2)3 × (-10)3

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Ex.13.1 Q.8

Compare the following numbers:

1. 2.7 × 1012; 1.5 × 108              

2. 4 × 1014; 3 × 1017

 

View Answer

Ex.13.2 Q.1

Using laws of exponents, simplify and write the answer in exponential form:

1. 32 × 34 × 38              

2. 615 ÷ 610               

3. a3 × a2            

4. 7x × 72         

5. (52)3 ÷ 53             

6. 25 × 55                  

7. a4 × b4               

8. (34)3             

9. (220 ÷ 215) × 23       

10. 8t ÷ 82

View Answer

Ex.13.2 Q.2

Simplify and express each of the following in exponential form:

1. (23 × 34 × 4) ÷ (3 × 32)         

2. [(52)3 × 54] ÷ 57        

3. 254 ÷ 53           

4. (3 × 72 × 118) ÷ (21 × 113)

5. 37 ÷ (34 × 33)     

6. 20 + 30 + 40    

7. 20 × 30 × 40  

8. (30 + 20) × 50   

9. (28 × a5) ÷ (43 × a3)   

10. (a5 ÷ a3) × a8        

11. (45 × a8 b3) ÷ (45 × a5 b2)   

12. (23 × 2)2

View Answer

Ex.13.2 Q.3

Say true or false and justify your answer:

1. 10 × 1011 = 10011      

2. 23 > 52       

3. 23 × 32 = 65       

4. 30 = (1000)0

View Answer

Ex.13.2 Q.4

Express each of the following as a product of prime factors only in exponential form:

1. 108 × 192       

2. 270        

3. 729 × 64        

4. 768

View Answer

Ex.13.2 Q.5

Simplify:

1. {(25)2 × 73} ÷ (83 × 7)        

2. (25 × 52 × t8) ÷ (103 × t4)        

3. (35 × 105 × 25) ÷ (57 × 65)

View Answer

Ex.13.3 Q.1

Write the following numbers in the expanded form:

279404, 3006194, 2806196, 120719, 20068

View Answer

Ex.13.3 Q.2

Find the number from each of the following expanded forms:

(a) 8 × 104 + 6 × 103 + 0 × 102 + 4 × 101 + 5 × 100

(b) 4 × 105 + 6 × 103 + 0 × 102 + 4 × 101 + 5 × 100

(c) 3 × 104 + 7 × 102 + 5 × 100

(d) 9 × 105 + 2 × 102 + 3 × 101

View Answer

Ex.13.3 Q.3

Express the following numbers in standard form:

1. 5,00,00,000         

2. 70,00,000             

3. 3,18,65,00,000           

4. 3,90,878

5. 39087.8           

5. 3908.78

View Answer

Ex.13.3 Q.4

Express the number appearing in the following statements in standard form:

(a) The distance between Earth and Moon is 384,000,000 m.

(b) Speed of light in vacuum is 300,000,000 m per s.

(c) Diameter of Earth id 1,27,56,000 m.

(d) Diameter of the Sun is 1,400,000,000 m.

(e) In a galaxy there are on an average 100,000,000,0000 stars.

(f) The universe is estimated to be about 12,000,000,000 years old.

(g) The distance of the Sun from the centre of the Milky Way Galaxy is estimated to be

300,000,000,000,000,000,000 m.

(h) 60,230,000,000,000,000,000,000 molecules are contained in a drop of water weighing 1.8 gm.

(i) The Earth has 1,353,000,000 cubic km of sea water.

(j) The population of India was about 1,027,000,000 in march, 2001.

View Answer

Complete NCERT Solutions: Classes 6 to 12, All Chapters

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