Question

Express the number appearing in the following statements in standard form:
Diameter of the sun is 1,400,000,000 m.

Answer 1

Hint: The standard form of a number is given as \[a \times {10^b}\] where a is a number with only one significant digit to the left of the decimal place and b is an integer.

Complete step by step answer:
Standard form is an easy way to express very large and very small numbers using powers of 10. It is also called the Scientific Notation. Any decimal number can be expressed in its standard form.

To write any number in standard form, place a decimal point after the first significant digit of the number and count the number of places the decimal point has moved. If the decimal point moved to the right, then the count is a negative number and if the decimal point moved to the left, the count is a positive number. Then express the result as the product of the new number with the power of 10 raised to the count we calculated.

The given number is 1,400,000,000 and we need to express this in its standard form.
So, first we just place the decimal digit after the first digit to get the number 1.4.

Then, we find the count by counting the number of places the decimal has moved from 1,400,000,000.0 to 1.4. The count is 9 and it is positive since the decimal point moved to its left.

Then the standard form is given as:

\[1,400,000,000m = 1.4 \times {10^9}m\]

Hence, the correct answer is \[1.4 \times {10^9}m\].


Note: You must not include the trailing zeros in the answer because the use of standard form is itself to reduce the space it takes to express the number.