Question

Which number is 0.0069 expressed in scientific notation? 6.9 × 10 4 6.9 × 10 –6 6.9 × 10 –4 6.9 × 10 –3

Answer 1

Given: The number = 0.0069 that has to be expressed in scientific notation

Concept: When we express any number in scientific notation then we shall consider two points.

(i) If we shift the decimal point from left to right after first (non-zero) digit then we count the number of shifted place of decimal and write them in terms of the negative power of 10. For example,  0.004789 = 4.789 ×10⁻³

(ii) If we shift the decimal point from right to left after first (non-zero) digit from the left end then we count the number of shifted place and write then in terms of the positive power of 10. For example,  4789.24 = 4.78924 ×10⁺³ = 4.78924 ×10³ Now, we shall convert the given number 0.0069 in scientific notation

0.0069  = 6.9 ×10⁻³ because we have shifted the decimal from left to right for three places that is after digit 6.

Hence, the last option 6.9 ×10⁻³ will be the correct option.