1.9 Laws of logarithms Quiz

1. Simplify $\log_{10}4+\log_{10}25$.

• A. $\log_{10}29$
• B. $1$
• C. $2$
• D. $100$

2. Write $2\ln x-\ln y$ as a single logarithm.

• A. $\ln\frac{x^{2}}{y}$
• B. $\ln(2x-y)$
• C. $\ln\frac{2x}{y}$
• D. $\ln\left(x^{2}-y\right)$

3. Solve $3^{x}=50$ to 3 s.f.

• A. $16.7$
• B. $2.81$
• C. $0.281$
• D. $3.56$

4. Find $\ln\left(e^{5}\right)+\ln1$.

• A. $6$
• B. $5$
• C. $0$
• D. $e^{5}$

5. A noise has intensity multiplied by $1000$. By how much does $L=10\log_{10}\left(\frac{I}{I_0}\right)$ increase?

• A. $3$ dB
• B. $10$ dB
• C. $30$ dB
• D. $1000$ dB