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laws-of-indices-and-square-cube-roots-l2 MCQ - Practice Questions with Answers

Solve 30 laws-of-indices-and-square-cube-roots-l2 questions for RAS/RPSC preparation.

Practice questions

Q1Which statement gives the meaning of 2^5 for Asha?

A 2 multiplied by itself five times
B 2 multiplied by 5
C 5 multiplied by itself two times
D 2 added five times
Explanation

2^5 means the base 2 used as a factor five times: 2 x 2 x 2 x 2 x 2 = 32, so option A is correct. Multiplying 2 by 5 (gives 10) or adding 2 five times (gives 10) misreads the exponent; '5 multiplied by itself two times' describes 5^2, not 2^5.

Q2Match the expression with its simplified form. I: (2^3)^2, II: 3^2 x 3^4, III: cube root of 125.

A I-2^6, II-3^6, III-5
B I-2^5, II-3^8, III-25
C I-4^5, II-9^6, III-15
D I-2^9, II-3^2, III-6
Explanation

Each item uses a different index law: (2^3)^2 = 2^(3x2) = 2^6 (power of a power multiplies exponents); 3^2 x 3^4 = 3^(2+4) = 3^6 (same base adds exponents); cube root of 125 = 5 because 5^3 = 125. So option A (I-2^6, II-3^6, III-5) is correct; B/C/D mix up these rules.

Q3Imran simplifies 4^3 x 4^2. Which answer is correct?

A 4^6
B 4^5
C 8^5
D 16^5
Explanation

Same-base multiplication adds the exponents: 4^3 x 4^2 = 4^(3+2) = 4^5, so B is correct. 4^6 wrongly multiplies the exponents (3 x 2); 8^5 and 16^5 wrongly change the base 4 into 8 or 16 instead of keeping it.

Q4Assertion: Expanding 7^5 divided by 7^2 into factors helps explain why the result is 7^3. Reason: Two equal factors of 7 cancel from the numerator and denominator, leaving three factors of 7.

A Both assertion and reason are true, and the reason correctly explains the assertion
B Both assertion and reason are true, but the reason does not explain the assertion
C The assertion is true, but the reason is false
D The assertion is false, but the reason is true
Explanation

Both parts are true: 7^5 divided by 7^2 becomes five factors of 7 over two factors of 7. Cancelling two common factors leaves three factors of 7, which is 7^3.

Q5Which option correctly defines a perfect square for Class 6 to 8 mathematics?

A A number obtained by adding a whole number to itself
B A number obtained by multiplying a whole number by itself
C A number obtained by multiplying three equal whole-number factors
D Any number whose last digit is 0, 1, 4, 5, 6, or 9
Explanation

A perfect square is obtained when a whole number is multiplied by itself, such as 12 times 12. Adding a number to itself gives a double, and three equal factors make a perfect cube; last digits are only a checking clue, not the meaning.

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More questions

6Using the law of indices for multiplication on equal bases, what is the simplified form of 4^3 x 4^2?

A4^5
B4^6
C16^5
D4^1

7In the index form 6^4, what is the base?

A4, because it is written above
B6, because it is the repeated factor
C24, because 6 is multiplied by 4
D10, because 6 and 4 are added

8Assertion: 2^4 x 3^4 can be written as 6^4. Reason: the product law permits a^n b^n = (ab)^n.

AAssertion true, reason false
BAssertion false, reason true
CBoth false
DBoth true, and the reason explains the assertion

9Simplify 3^2 x 3^4 using the same-base multiplication law.

A3^6
B9^6
C3^8
D3^2

10Match the learner error with the misconception. I: 9^2 = 18, II: square root of 225 = 112.5, III: 5^0 = 0.

AI exponent as multiplication, II root as halving, III zero exponent misunderstood
BI root as halving, II exponent as multiplication, III cube-root confusion
CI unlike-base error, II cancellation error, III square-root error
DI correct, II correct, III correct

11A learner says, 2^4 = 8. Which misconception is most likely shown here?

AThe learner is adding 2 and 4
BThe learner is treating 2^4 as 2 x 4
CThe learner is subtracting 4 from 2
DThe learner is using the square root of 64

12Which pair of statements is correct about square and cube roots?

ASquare root of 144 is 72; cube root of 64 is 8
BSquare root of 144 is 12; cube root of 64 is 8
CSquare root of 144 is 12; cube root of 64 is 4
DSquare root of 144 is 14; cube root of 64 is 6

13Devika writes 2^3 x 3^3 as 6^3. Why is this allowed?

ABecause the bases are equal
BBecause the same exponent applies to both factors
CBecause all unlike bases can be multiplied in powers
DBecause 2 + 3 = 5 and 3 + 3 = 6

14Which statement is incorrect about the laws of indices for non-zero equal bases?

AIn a^m x a^n, the exponents are added.
BIn a^m divided by a^n, common factors cancel.
CIn (a^m)^n, the exponents are multiplied.
DIn a^m divided by a^n, the exponents are always added.

15A learner says, "7^2 = 14." Which teacher question best helps the learner correct the idea?

ADid you remember the rule from the board?
BShould we add 7 and 2 again?
CHow many sevens are being multiplied?
DIs 14 an even number?

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