State two ways to save energy.

A child makes a poster on a chart paper drawing a square A B C D of side 14 cm. She draws four circles with centre A ,\ B ,\ C and D in which she suggests different ways to save energy. The circles are drawn in such a way that each circle touches externally two of the three remaining circles. In the shaded region she write a message Save Energy. Find the perimeter and area of the shaded region.

State two ways to minimise the impact of global warming.

State two ways to prevent the rusting of iron.

State two ways to increase the speed of rotation of a D.C. motor.

List in tabular form any three chemical properties on the basis of which metals and non-metals are differentiated. State two ways to prevent the rusting of iron.

In Young.s double slit experiment, what is meant by .fringe separation. ? State two ways of increasing the fringe width, without changing the source of light.

State two ways in which Resonance differs from Forced vibrations.

State two ways by which the frequency of a note given out by a stretched vibrating string can be increased.

State two ways, by which a saturated solution can be changed to unsaturated solution.

State two ways by which the strength of magnetic field of an electromagnet can be increased.