Infrared radiation is detected by

In a simple harmonic oscillator, at the mean position

1 mole of a gas with $$\gamma = 7/5$$ is mixed with $$1$$ mole of a gas with $$\gamma = 5/3,$$ then the value of $$\gamma $$ for the resulting mixture is

If a spring has time period $$T,$$ and is cut into $$n$$ equal parts, then the time period of each part will be