What is the effect of pressure on the speed of sound in a medium, if pressure is doubled at constant temperature?

Two sound waves having wavelengths $$5.0 \mathrm{~m}$$ and $$5.5 \mathrm{~m}$$ propagates in a gas with velocity 300 $$\mathrm{m} / \mathrm{s}$$. The number of heats produced per second is

In biprism experiment, $$6^{\text {th }}$$ bright band with wavelength '$$\lambda_1$$' coincides with $$7^{\text {th }}$$ dark band with wavelength '$$\lambda_2$$' then the ratio $$\lambda_1: \lambda_2$$ is (other setting remains the same)

The time period of a satellite of earth is 5 hours. If the separation between the earth and the satellite will satellite is increased to four times the previous value, the new time period of the satellite will be