Describe the construction of a box type solar cooker and show it with the help of a diagram. How is the rise in temperature obtained in this set up? Mention two advantages and two limitations of solar cookers.

With the help of a diagram describe the working of a windmill to lift underground water.

What is tidal energy? How tidal energy is harnessed? Explain with a diagram.

A nucleus has a mass number $‘m’$ and atomic number $‘n’$ How will these numbers change in the following emissions per atom?

One alpha particle

A nucleus has a mass number$‘m’$ and atomic number $‘n’$ How will these numbers change in the following emissions per atom?

A positron.

What are the environmental consequences of the increasing demand for energy? What steps would you suggest to reduce energy consumption.