Question 1

Significant figures in a measurement are:

Accepted Answer

The reliably known digits plus the first uncertain digit. They convey the precision with which the measurement was made.

Question 2

Zeros lying between two non-zero digits are:

Accepted Answer

Always significant. In 2.0034, for example, all five digits count.

Question 3

Zeros written to the left of the first non-zero digit are:

Accepted Answer

Not significant. In 0.0025 the leading zeros merely fix the decimal point, so there are two significant figures.

Question 4

Trailing zeros written after the decimal point are:

Accepted Answer

Significant. Writing 1.230 rather than 1.23 asserts that the final zero was measured.

Question 5

In addition and subtraction, the result should be rounded to the:

Accepted Answer

Least number of decimal places among the quantities. The result cannot be more precise in its last decimal place than the crudest measurement used.

Question 6

In multiplication and division, the result should be rounded to the:

Accepted Answer

Least number of significant figures among the quantities. Relative uncertainties combine, so the least precise factor governs the result.

Question 7

When rounding, a digit of 5 followed by no other digits is conventionally handled by:

Accepted Answer

Rounding so that the preceding digit becomes even. This "round half to even" convention avoids a systematic bias when many numbers are rounded.

Question 8

Exact numbers, such as the 2 in the formula for the circumference 2\pi r, have:

Accepted Answer

An infinite number of significant figures. Being definitions rather than measurements, they never limit the precision of a result.

Question 9

The number of significant figures in 0.00520 is:

Accepted Answer

3. The leading zeros are not significant; the digits 5, 2 and the trailing 0 are.

Question 10

The number of significant figures in 1.230 is:

Accepted Answer

4. The trailing zero after the decimal point is significant.

Question 11

The number of significant figures in 2.0034 is:

Accepted Answer

5. The zeros lie between non-zero digits, so all five figures count.

Question 12

The number of significant figures in 0.0025 is:

Accepted Answer

2. Only 2 and 5 are significant; the leading zeros are placeholders.

Question 13

The number of significant figures in 4.320 	imes 10^3 is:

Accepted Answer

4. In scientific notation only the mantissa counts, and its trailing zero is significant.

Question 14

The number of significant figures in 6.02 	imes 10^{23} is:

Accepted Answer

3. The power of ten is not counted; only the three digits of the mantissa are significant.

Question 15

The number of significant figures in 0.0001234 is:

Accepted Answer

4. The four leading zeros are placeholders, leaving 1, 2, 3 and 4.

Question 16

The sum 2.5 + 3.42 correctly rounded is:

Accepted Answer

5.9. The arithmetic gives 5.92, but 2.5 has only one decimal place, so the answer is 5.9.

Question 17

The product 2.5 	imes 3.42 correctly rounded is:

Accepted Answer

8.6. The arithmetic gives 8.55, but 2.5 has only two significant figures, so the answer is 8.6.

Question 18

The sum 12.36 + 1.2 correctly rounded is:

Accepted Answer

13.6. The arithmetic gives 13.56; rounding to one decimal place gives 13.6.

Question 19

The product 1.234 	imes 2.1 correctly rounded is:

Accepted Answer

2.6. The factor 2.1 has two significant figures, so the result is quoted to two.

Question 20

The number 2.746 rounded to three significant figures is:

Accepted Answer

2.75. The digit after the third figure is 6, so the third figure is rounded up.

Significant Figures & Rounding — MH-CET Physics MCQs with Solutions

Questions with solutions