Question:
If $Log_{10}7=0.8451$ then the position of the first significant figure of $7^{-20}$ is
If $Log_{10}7=0.8451$ then the position of the first significant figure of $7^{-20}$ is
Updated On: May 14, 2024
- 16
- 17
- 20
- 15
Hide Solution
Verified By Collegedunia
The Correct Option is B
Solution and Explanation
Let $x=7^{-20}$
$\log _{10} x=-20 \log _{10} 7$
$=-20(0.8451)$
$=-16.902$
Hence, the first significant figure is $17 .$
$\log _{10} x=-20 \log _{10} 7$
$=-20(0.8451)$
$=-16.902$
Hence, the first significant figure is $17 .$
Was this answer helpful?
4
2
Top Questions on Significant figures
- For an experimental expression \( y = \frac{32.3 \times 1125}{27.4} \), where all the digits are significant. Then to report the value of \( y \), we should write:
- JEE Main - 2025
- Physics
- Significant figures
- Number of significant figures in 42306, 0.0007 and \(6.5 \times 10^{-3}\) are respectively.
- UPCATET - 2025
- Physics
- Significant figures
- The number of significant figures in 0.03240 is
- AP EAPCET - 2025
- Physics
- Significant figures
- Express the final answer to the proper number of significant figures: \[ 18.0 + 11.515 + 13.2 = \ldots \]
- KEAM - 2025
- Physics
- Significant figures
- Time periods of oscillation of the same simple pendulum measured using four different measuring clocks were recorded as 4.62 s, 4.632 s, 4.6 s and 4.64 s. The arithmetic mean of these reading in correct significant figure is.
- JEE Main - 2024
- Physics
- Significant figures
View More Questions
Questions Asked in KCET exam
- If \( A \) is a square matrix of order \( 3 \times 3 \), \( \det A = 3 \), then the value of \( \det(3A^{-1}) \) is:
- KCET - 2025
- Matrices
A block of certain mass is placed on a rough floor. The coefficients of static and kinetic friction between the block and the floor are 0.4 and 0.25 respectively. A constant horizontal force \( F = 20 \, \text{N} \) acts on it so that the velocity of the block varies with time according to the following graph. The mass of the block is nearly (Take \( g = 10 \, \text{m/s}^2 \)):
- KCET - 2025
- work, energy and power
- Given, a current carrying wire of non-uniform cross-section, which of the following is constant throughout the length of the wire?
- KCET - 2025
- Current electricity
- If the number of terms in the binomial expansion of \((2x + 3)^n\) is 22, then the value of \(n\) is:
- KCET - 2025
- Binomial theorem
- Ethyl alcohol is heated with concentrated sulphuric acid at 413 K (140°C). The major product formed is
- KCET - 2025
- Organic Chemistry
View More Questions
Concepts Used:
Significant Figures
The significant figures of a given number are those significant or important digits, which convey the meaning according to its accuracy. For example, 6.658 has four significant digits. These substantial figures provide precision to the numbers. They are also termed as significant digits.
Rules for Significant Figures:
- All non-zero digits are significant. 198745 contains six significant digits.
- All zeros that occur between any two non zero digits are significant. For example, 108.0097 contains seven significant digits.
- All zeros that are on the right of a decimal point and also to the left of a non-zero digit is never significant. For example, 0.00798 contained three significant digits.
- All zeros that are on the right of a decimal point are significant, only if, a non-zero digit does not follow them. For example, 20.00 contains four significant digits.
- All the zeros that are on the right of the last non-zero digit, after the decimal point, are significant. For example, 0.0079800 contains five significant digits.
- All the zeros that are on the right of the last non-zero digit are significant if they come from a measurement. For example, 1090 m contains four significant digits.