8th Grade > Mathematics
EXPONENTS AND POWERS MCQs
:
(3ab)2(−5a2bc4)2
= (9a2b2) × (25a4b2c8)
= 225a6b4c8
Exponent of c = 8
:
A
The value of (4−7 ÷ 4−10 ) × 4−5 is 16−1.
(4−7÷ 4−10)×4−5
=(4−74−10) ×4−5
=4−7+10×4−5 (∵aman= am−n)
=43×4−5
⇒43−5 (∵am×an= am+n)
=4−2=142
=116
=16−1
:
A
We know that for a non-zero integer a and any integer m,
a−m=1am.
∴6−2=162
⟹16−2=62=36
Similarly, 13−3=33=27 and 15−2=52=25.
⟹(16−2−13−3)÷15−2=(36−27)÷25
=925
=3252
=(35)2 (∵ambm=(ab)m
:
A
8,780,000,000,000=878×1010
=8.78×102×1010
=8.78×1012
=87.8×10−1×1012
=87.8×1011
(Using am×an=am+n)
:
C
1 micron = 10−6 m.
:
A
((2)2)2× (33 ÷42) ÷ 32
= 42 ×2716× 19 (∵(am)n=amn)
= 16 × 2716× 19
= 279
= 3
:
A
27 is 2 multiplied by itself, 7 times.
So, 27=2×2×2×2×2×2×2=128
:
B
210= (25)2 = (2×2×2×2×2)2 = 32×32 = 1024
102 = 10×10 = 100
Since 1024 > 100 so, 210 is greater than 102.