R.S Aggarwal Class 8 Chapter 2 Exponents Test paper Solution
The 2nd Chapter of RS Aggarwal book of Class 8 is about exponents and in this post we have provided complete written solution for the test paper 2 along with a video solution. The solutions are prepared by our team of expert teachers.
Test Paper 2
A) 1) Evaluate:
i) 3-4 ii) (-4)3 iii) (3/4)-2 iv) (-2/3)-5 v) (5/7)0
Ans:
i) 3-4 = (1/3)4 = 1/81
ii) -43= – 64
iii) (3/4)-2 = (4/3) 2 = 42/32= 16/9
iv) (-2/3)-5 = (-3/2)5 = -243/32
v) (5/7)0 = 1
2) Evaluate: {(-2/3)3}-2
Ans: {(-2/3)3}-2
= {(-23/33)} -2
= [-8/27]-2
= [-27/8]2
= -272/82
= 729/64
3) Simplify: (3-1+ 6-1) ÷ (3/4)-1
Ans: (3-1+ 6-1) ÷ (3/4)-1
= (1/3) + (1/6) ÷ (4/3)
= [(2+1)/6] ÷ (4/3)
= (1/2) × (3/4)
= 3/8
4) By what number should (-2/3)-3 be divided so that the quotient is (4/9)-2?
Ans: let the required number be m
∴ (-2/3)-3/m= (4/9)-2
Or, (-3/2)3/m = (9/4)2
Or, (-3/2)3 ÷ (9/4)2= m
Or, (-27/8) × (16/81) = m
Or, m = (-2/3)
∴ (-2/3)-3 should be divided by (-2/3) so that the quotient is (4/9)-2.
5) By what number should (-3)-1 be multiplied so that the product becomes 6-1?
Ans: Let the required number be m
∴ (-3)-1×m = 6-1
Or, (-1/3) × m = (1/6)
Or, m = (-1/2)
∴ (-3)-1 should be multiplied with (-1/2) so the product becomes 6-1
6) Express each of the following in standard form:
i) 345 ii) 180000 iii) 0.000003 iv) 0.000027
Ans The standard form of the given numbers are
i) 345 = 3.45×100 = 3.45×102
ii) 180000 = 1.8 × 100000 = 1.8×105
iii) 0.000003 = 3/1000000 = 3×10-6
iv) 0.000027 = 2.7/100000 = 2.7×10-5
B) Mark (✓) against the correct answer in each of the following.
7) The value of (-3)-3 is
a) -27
b) 9
c) (-1/27) (✓)
d) (1/27)
Ans: (-3)-3 = (-1/3)3 = -1/27
8) The value of (3/4)-3 is
a) -27/64
b) 64/27 (✓)
c) -9/4
d) 27/64
Ans: (3/4)-3 = (4/3)3 = 43/33 = 64/27
9) 3-6 ÷ 34 = ?
a) 3‑2
b) 32
c) 3-10 (✓)
d) 310
Ans: 3-6 ÷ 34 = (1/3)6 × (1/3)4 = 3-10
10) If (5/12)-4× (5/12)3x = (5/12)5 then x = ?
a) -1
b) 1
c) 2
d) 3
11) (3/5)0=?
a) (5/3)
b) (3/5)
c) 1 (✓)
d) 0
Ans : (3/5)0 = 30/50 = 1
12) (-6/5)-1 =?
a) 6/5
b) -6/5
c) 5/6
d) -5/6 (✓)
Ans: (-6/5)-1= (-5/6)
13) (-1/3)3 =?
a) (-1/9)
b) 1/9
c) -1/27
d) 1/27 (✓)
Ans: (1/3)3 = 1/33= 1/27
C) 14) Fill in the blanks.
i) 360000 written in standard form is __6×105__
ii) 0.0000123 written in standard form is _23×10 -5_
iii) (-2/3)-2= __(-9/4)__
iv) 3×10-3 in usual form is ____003______
v) 5.32×10-4 in usual form is ___000532___