The life on earth is protected form ultraviolet radiation of the sun.

The threshold wavelength of tungsten is 2.76 xx 10^-5 cm .What will be the maximum kinetic energy of electrons ejected in each of the following cases: if ultraviolet radiation of wavelength lambda = 1.80 xx 10^-5 cm .

How photosynthesis protect us from harmful radiations.

All life on earth is bottled solar energy. Justify.

Solve the following examples / numerical problems: The time taken by the earth to complete on revolution around the Sun is 3.156 xx 10^7 s. The distance between the earth and the sun is 1.5 xx 10^11 m . Find the speed of revolution of the earth.

The mean distance of Mars from the sun in 1.524 times that of the Earth from the sun. Find the number of years requires for Mars make one revolution about the Sun.

The angular diameter of the sun is 1920". If the distance of the sun from the earth is 1.5xx10^(11) m, what is the linear diameter of the sun ?

If the earth is at one-fourth of its present distance from the sun, the duration of the year would be

The first form of life on earth consisting of nucleic acid along with inorganic and organic molecules are known as................

Solve the following examples / numerical problems: Assuming that the earth performs uniform circular motion around the Sun, find the centripetal acceleration of the earth. [Speed of the earth =3 xx10^4 m/s, distance between the earth and the Sun= 1.5xx10^11 m]