Which of the following is less than 6.5*10^-5?
A. 1.4*10^.3
B. 2.5*10^-4
C. 7.8*10^-5
D. 4.6*10^6
Is the answer A?
To determine which of the options is less than 6.5*10^-5, we need to compare the values.
Option A: 1.4*10^.3
This number can be rewritten as 1.4 * 10^0.3, which is approximately 1.4 * 2.0 = 2.8.
Option B: 2.5*10^-4
This number can be rewritten as 2.5 * 0.0001 = 0.00025.
Option C: 7.8*10^-5
This number can be rewritten as 7.8 * 0.00001 = 0.000078.
Option D: 4.6*10^6
This number can be rewritten as 4.6 * 1,000,000 = 4,600,000.
Now, comparing these values to 6.5 * 10^-5:
2.8 > 6.5 * 10^-5,
0.00025 < 6.5 * 10^-5,
0.000078 < 6.5 * 10^-5,
4,600,000 > 6.5 * 10^-5.
None of the options are less than 6.5 * 10^-5. Therefore, the correct answer is none of the above.
To determine which of the given values is less than 6.5*10^-5, we can compare the exponents of the numbers first. In scientific notation, the exponent represents the order of magnitude of the number. The smaller the exponent, the smaller the number.
In this case:
- 6.5*10^-5 has an exponent of -5.
- 1.4*10^0 has an exponent of 0.
- 2.5*10^-4 has an exponent of -4.
- 7.8*10^-5 has an exponent of -5.
- 4.6*10^6 has an exponent of 6.
Comparing the exponents, we can see that -5 is smaller than 0, -4, and 6. However, it is the same as -5. The exponent -5 indicates a much smaller number than the exponents 0, -4, and 6.
So, the correct answer should be the option with an exponent smaller than -5. Among the given choices, only option C - 7.8*10^-5 - has an exponent smaller than -5.
Therefore, the correct answer is C, not A.