RS Aggarwal Solutions: Exercise 2C - Exponents | Mathematics (Maths) Class 8 PDF Download

Q.1. Tick (✓) the correct answer
The value of is

(a)
(b)
(c)
(d)
Ans.
(c) 
 

Q.2. Tick (✓) the correct answer

The value of (−3)⁻⁴ is
(a) 12
(b) 81
(c)
(d)
Ans.
(d)


Q.3. Tick (✓) the correct answer
The value of (−2)⁻⁵ is
(a) −32
(b)
(c) 32
(d)
Ans.
(b)


Q.4. Tick (✓) the correct answer
(2⁻⁵ ÷ 2⁻²) = ?
(a)
(b)
(c)
(d) 1/8
Ans.
(d) 1/8


Q.5. Tick (✓) the correct answer
The value of (3⁻¹ + 4⁻¹)⁻¹ ÷ 5⁻¹ is
(a)
(b)
(c)
(d)
Ans.
(b  


Q.6. Tick (✓) the correct answer

(a)
(b)
(c) 29
(d)
Ans.
(c) 29

=2² + 3² + 4²
=4 + 9 + 16
= 29

Q.7. Tick (✓) the correct answer

(a)
(b)
(c)
(d)
Ans.
(a)

= {3³ − 2³}÷4³
= {27−8} ÷ 64
= 19 ÷ 64
=

Q.8. Tick (✓) the correct answer

(a)
(b) 16
(c)
(d) -16
Ans.
(a) 


Q.9. Tick (✓) the correct answer
The value of x for which
(a) −1
(b) 1
(c) 2
(d) 3
Ans.
(d) 3

⇒ 3x − 4 = 5
3x = 9
or

Q.10. Tick (✓) the correct answer
If (2^{3x − 1} + 10) ÷ 7 = 6, then x is equal to
(a) −2
(b) 0
(c) 1
(d) 2
Ans.
(d) 2

On cross multiplying:
(2^3x−1 + 10) × 1=6 × 7 = 42
⇒ 2^3x-1  = 42 -10
⇒2^3x-1 = 32
⇒ 2^3x-1  = 25
⇒ 3x-1 = 5
⇒ 3x = 6
Therefore, x =  2

Q.11. Tick (✓) the correct answer

(a)
(b)
(c) 1
(d) 0
Ans.
(c) 1

Using the law of exponents=1 :


Q.12. Tick (✓) the correct answer

(a)
(b)
(c)

(d) none of these
Ans.
(c)



Q.13. Tick (✓) the correct answer

(a)
(b)
(c)
(d)
Ans.
(d)


Q.14. Tick (✓) the correct answer

(a)
(b)
(c)
(d)
Ans.
(b)


Q.15. Tick (✓) the correct answer
3670000 in standard form is
(a) 367 × 10⁴
(b) 36.7 × 10⁵
(c) 3.67 × 10⁶
(d) none of these
Ans.
(c) 3.67×10⁶
3670000=367×10⁴ = 3.67 × 100 × 10⁴ = 3.67 × 10² × 10⁴ = 3.67 × 10⁽²⁺⁴⁾ = 3.67 × 10⁶

Q.16.

Tick (✓) the correct answer

0.0000463 in standard form is

(a) 463 × 10⁻⁷

(b) 4.63 × 10⁻⁵

(c) 4.63 × 10⁻⁹

(d) 46.3 × 10⁻⁶
Ans.
(b) 4.63×10⁻⁵


Q.17. Tick (✓) the correct answer
0.000367 × 104 in usual form is
(a) 3.67
(b) 36.7
(c) 0.367
(d) 0.0367
Ans.
(a) 3.67