Radioactive decay provides an internal source of heat for the earth. This helps in the formation of which type
of rocks ?
(a) Igneous (b) Sedimentary (c) Metamorphic (d) All of the above
The greatest seasonal contrast of insolation on the earth is in which of the following latitudinal zones ?
(a) Equatorial (b) Tropical (c) Temperatre (d) polar
A motor vehicle is moving on a circle with a uniform speed. The net acceleration of the vehicle is -
(a) zero
(b) towards the centre of the circle
(c) away from the centre along the radius of the circle
(d) perpendicular to the radius and along the velocity
In India, increase in population and diversion of agricultural land for non-agricultural purposes have resulted
in the decrease of -
(a) forested land (b) cultivable wasteland
(c) net sown area (d) double-cropped area
Two atoms are said to be isotopes if -
(a) they have the same atomic number but different mass numbers
(b) they have the same number of neutrons but different mass numbers
(c) the sum of the number of protons and neutrons is the same, but the number of protons is different
(d) they have the same number of neutrons but different modes of radioactive decay