NCERT Solutions For Class 8 Maths Chapter 12 Ex 12.2
ncert solutions for class 8 maths chapter 12, Exercise 12.2 involve complete answers for each question in the exercise 12.2. The solutions provide students a stretegic methods to prepare for their exam. Class 8 Maths Chapter 8 Exponents and powers Exercise 12.2 questions and answers helps students to perform better in exam and it will clear doubts definitely. Students will find it extremely easy to understand the questions and learn solving the problems.NCERT Solutions for Class 8 Maths Chapter 8 Exponents and powers Exercise 12.2 prepared by our subject matter experts in very delicate, easy and creative way.
Question 1:Express the following numbers in standard form.
(i) 0.0000000000085 (ii) 0.00000000000942 (iii) 6020000000000000 (iv) 0.00000000837
(v) 31860000000
Answer:(i) 0.0000000000085 = 8.5 × 10−12
(ii) 0.00000000000942 = 9.42 × 10−12
(iii) 6020000000000000 = 6.02 × 1015
(iv) 0.00000000837 = 8.37 × 10−9
(v) 31860000000 = 3.186 × 1010
Question 2:
Express the following numbers in usual form.
(i) 3.02 × 10−6 (ii) 4.5 × 104
(iii) 3 × 10−8 (iv) 1.0001 × 109
(v) 5.8 × 1012 (vi) 3.61492 × 106
Answer:(i) 3.02 × 10−6 = 0.00000302
(ii) 4.5 × 104= 45000
(iii) 3 × 10−8 = 0.00000003
(iv) 1.0001 × 109 = 1000100000
(v) 5.8 × 1012 = 5800000000000
(vi) 3.61492 × 106 = 3614920
Question 3:
Express the number appearing in the following statements in standard form.
(i) 1 micron is equal to m.
(ii) Charge of an electron is 0.000, 000, 000, 000, 000, 000, 16 coulomb.
(iii) Size of a bacteria is 0.0000005 m
(iv) Size of a plant cell is 0.00001275 m
(v) Thickness of a thick paper is 0.07 mm
Answer:(i) = 1 × 10-6
(ii) 0.000, 000, 000, 000, 000, 000, 16 = 1.6 × 10-19
(iii) 0.0000005 = 5 × 10-7
(iv) 0.00001275 = 1.275 × 10-5
(v) 0.07 = 7 × 10-2
Question 4:
In a stack there are 5 books each of thickness 20 mm and 5 paper sheets each of thickness 0.016 mm. What is the total thickness of the stack?
Answer:
Thickness of each book = 20 mm
Hence, thickness of 5 books = (5 × 20) mm = 100 mm
Thickness of each paper sheet = 0.016 mm
Hence, thickness of 5 paper sheets = (5 × 0.016) mm = 0.080 mm
Total thickness of the stack = Thickness of 5 books + Thickness of 5 paper sheets
= (100 + 0.080) mm
= 100.08 mm
= 1.0008 × 102 mm
