1. **Problem Statement:** Two tuning forks have frequencies $n_1 = 320$ Hz and $n_2 = 340$ Hz. The velocity of sound in air is $v = 326.4$ m/s. We need to find the difference in their wavelengths, i.e., $\lambda_1 - \lambda_2$. 2. **Formula Used:** The wavelength $\lambda$ of a wave is related to its velocity $v$ and frequency $n$ by the formula: $$\lambda = \frac{v}{n}$$ Since we have two frequencies, their wavelengths are: $$\lambda_1 = \frac{v}{n_1}, \quad \lambda_2 = \frac{v}{n_2}$$ 3. **Important Rule:** Since $n_1 < n_2$, it follows that $\lambda_1 > \lambda_2$. The difference in wavelengths is: $$\lambda_1 - \lambda_2 = \frac{v}{n_1} - \frac{v}{n_2} = v \left( \frac{1}{n_1} - \frac{1}{n_2} \right)$$ 4. **Substitute the values:** $$\lambda_1 - \lambda_2 = 326.4 \left( \frac{1}{320} - \frac{1}{340} \right)$$ Calculate inside the parentheses: $$\frac{1}{320} = 0.003125, \quad \frac{1}{340} \approx 0.0029412$$ So, $$0.003125 - 0.0029412 = 0.0001838$$ 5. **Calculate the difference:** $$\lambda_1 - \lambda_2 = 326.4 \times 0.0001838 \approx 0.06 \text{ meters}$$ **Final Answer:** The difference in wavelengths is $0.06$ meters.