Exponents and Powers Class 8 Extra Questions Maths Chapter 12
Extra Questions for Class 8 Maths Chapter 12 Exponents and Powers
Exponents and Powers Class 8 Extra Questions Very Short Answer Type
Question 1.
Find the multiplicative inverse of:
(i) 3
-3
(ii) 10
-10
Solution:
Question 2.
Expand the following using exponents.
(i) 0.0523
(ii) 32.005
Solution:
Question 3.
Simplify and write in exponential form.
Solution:
Question 4.
Simplify the following and write in exponential form.
Solution:
Question 5.
Express 8
-4
as a power with the base 2.
Solution:
We have 8 = 2 × 2 × 2 = 2
3
8
-4
= (2
3
)
-4
= 2
3×(-4)
= 2
-12
Question 6.
Simplify the following and write in exponential form.
(i) (3
6
÷ 3
8
)
4
× 3
-4
(ii) \(\frac { 1 }{ 27 }\) × 3
-3
Solution:
Question 7.
Find the value of k if (-2)
k+1
× (-2)
3
= (-2)
7
Solution:
(-2)
k+1
× (-2)
3
= (-2)
7
⇒ (-2)
k+1+3
= (-2)
7
⇒ (-2)
k+4
= (-2)
7
⇒ k + 4 = 7
⇒ k = 3
Hence, k = 3.
Question 8.
Simplify the following:
Solution:
Question 9.
Find the value of \(\left[ \left( -\frac { 3 }{ 4 } \right) ^{ -2 } \right] ^{ 2 }\)
Solution:
Question 10.
Write the following in standard form
(i) 0 0035
(ii) 365.05
Solution:
Exponents and Powers Class 8 Extra Questions Short Answer Type
Question 11.
Find the value of P if
Solution:
Question 12.
Solution:
Question 13.
Find the value of x if
Solution:
⇒ 3 + x = 18 [Equating the powers of same base]
x = 18 – 3 = 15
Question 14.
Solve the following: (81)
-4
÷ (729)
2-x
= 9
4x
Solution:
Question 15.
Solution:
Question 16.
Solution:
Question 17.
Find x so that (-5)
x+1
× (-5)
5
= (-5)
7
(NCERT Exemplar)
Solution:
(-5)
x+1
× (-5)
5
= (-5)
7
(-5)
x+1+5
= (-5)
7
{a
m
× a
n
= a
m+n
}
(-5)
x+6
= (-5)
7
On both sides, powers have the same base, so their exponents must be equal.
Therefore, x + 6 = 7
x = 7 – 6 = 1
x = 1.
