Q. When multiplying 2.5 and 3.42, how many significant figures should the result have?
A.
2
B.
3
C.
4
D.
5
Solution
The result should have the same number of significant figures as the measurement with the least significant figures, which is 2.5 (2 significant figures).
Q. When multiplying 3.00 and 2.5, how many significant figures should the answer have?
A.
2
B.
3
C.
4
D.
5
Solution
In multiplication, the result should have the same number of significant figures as the factor with the least significant figures. 3.00 has 3 significant figures and 2.5 has 2 significant figures, so the answer should have 2 significant figures.
Q. When multiplying 3.00 by 2.5, how many significant figures should the answer have?
A.
2
B.
3
C.
4
D.
5
Solution
In multiplication, the result should have the same number of significant figures as the factor with the least significant figures. 3.00 has 3 significant figures and 2.5 has 2 significant figures, so the answer should have 2 significant figures.
Q. When multiplying 3.24 by 2.1, what is the correct number of significant figures in the final answer?
A.
4
B.
3
C.
2
D.
1
Solution
In multiplication, the result should have the same number of significant figures as the factor with the least significant figures. 3.24 has 3 significant figures and 2.1 has 2 significant figures, so the answer should have 2 significant figures.
Q. When subtracting 5.678 from 10.0, how should the answer be rounded?
A.
4.32
B.
4.3
C.
4.4
D.
4.00
Solution
In subtraction, the result should be rounded to the least number of decimal places. 10.0 has one decimal place and 5.678 has three, so the answer should be rounded to one decimal place: 4.32 becomes 4.3.
Q. Which of the following is the correct representation of 0.0004500 in scientific notation?
A.
4.500 x 10^-4
B.
4.5 x 10^-4
C.
4.5000 x 10^-4
D.
4.5 x 10^-5
Solution
In scientific notation, all non-zero digits and any trailing zeros after the decimal point are significant. Therefore, 0.0004500 is expressed as 4.500 x 10^-4.
Q. Which of the following numbers has the least significant figures?
A.
0.00560
B.
0.0560
C.
0.560
D.
5.60
Solution
0.00560 has 3 significant figures, 0.0560 has 3 significant figures, 0.560 has 3 significant figures, and 5.60 has 3 significant figures. However, 0.00560 is the smallest number, but all have the same count of significant figures.
Q. Which of the following numbers has the most significant figures?
A.
0.00789
B.
7890
C.
7.890 x 10^3
D.
0.07890
Solution
7.890 x 10^3 has 4 significant figures, while the others have 3, 3, and 4 respectively, but the leading zeros in the first and last options do not count.
Q. Which of the following operations will yield a result with the least number of significant figures?
A.
5.00 + 2.0
B.
3.00 x 4.0
C.
6.0 / 2.00
D.
1.5 - 0.50
Solution
In the operation 3.00 x 4.0, 3.00 has three significant figures and 4.0 has two. The result will have two significant figures, which is the least among the options.
Understanding significant figures is crucial for students preparing for exams, as it directly impacts the accuracy of numerical answers. Practicing MCQs and objective questions on significant figures helps reinforce this concept, ensuring you can tackle important questions with confidence. By mastering significant figures, you enhance your exam preparation and improve your overall performance in both school and competitive exams.
What You Will Practise Here
Definition and importance of significant figures in scientific calculations.
Rules for determining significant figures in different types of numbers.
How to perform calculations involving significant figures, including addition, subtraction, multiplication, and division.
Common examples and practice questions to solidify your understanding.
Identifying significant figures in measurements and their implications.
Application of significant figures in real-world scenarios and experiments.
Tips and tricks for quickly identifying significant figures in MCQs.
Exam Relevance
Significant figures are a key topic in various examinations, including CBSE, State Boards, NEET, and JEE. Questions often focus on identifying significant figures in given numbers, performing calculations while maintaining the correct number of significant figures, and interpreting results in the context of scientific data. Familiarity with this topic can help you tackle both direct and application-based questions effectively.
Common Mistakes Students Make
Confusing leading zeros with significant figures, often miscounting them.
Neglecting to adjust the number of significant figures in calculations, leading to incorrect answers.
Overlooking the rules for significant figures in multiplication and division compared to addition and subtraction.
Failing to recognize that trailing zeros in a whole number without a decimal point are not significant.
FAQs
Question: What are significant figures? Answer: Significant figures are the digits in a number that contribute to its precision, including all non-zero digits, any zeros between significant digits, and trailing zeros in the decimal portion.
Question: How do I determine the number of significant figures in a measurement? Answer: Count all non-zero digits, any zeros between them, and any trailing zeros in a decimal number. Leading zeros are not counted.
Ready to enhance your understanding of significant figures? Dive into our practice MCQs and test your knowledge to ensure you are well-prepared for your exams!
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