Radioactive disintegration differs from a chemical change in being

The maximum energy in the thermal radiation from a hot source occurs at a wavelength of $11 \times 10^{-5} \text{ cm}$. According to Wien's law,the temperature of the source (on Kelvin scale) will be $n$ times the temperature of another source (on Kelvin scale) for which the wavelength at maximum energy is $5.5 \times 10^{-5} \text{ cm}$. The value of $n$ is

Steam at $100\,^{\circ}C$ is passed into $1.1\,kg$ of water contained in a calorimeter of water equivalent $0.02\,kg$ at $15\,^{\circ}C$ until the temperature of the calorimeter rises to $80\,^{\circ}C$. The mass of steam condensed in kilograms is:

Which of the following relations is true?

What does the given structural formula represent?

If the impurity in a metal has a greater affinity for oxygen and is more easily oxidised than the metal,then the purification of metal may be carried out by