Haneet Gandhi and Yukti Sharma Solutions for Chapter: Our Natural Resources, Exercise 2: PREVIOUS YEARS' QUESTIONS

$3.7 \mathrm{kg}$ of fuel is completely burnt to give off $1.665\times {10}^8$ joules of energy. The calorific value of the fuel in the standard unit is:

Which one of the following is not a product of petroleum?

The change in seasons on the earth occurs because _____.

Renu's grandmother shows her a dried-up well and tells her that 15-20 years ago, there was water in the well, but now it has completely dried up. What could be the reason(s) for the drying up of water in the well?

I. The soil around the trees, well and nearby area is now covered with cement.

II. A lot of boring pumps have come up in the nearby area.

Ill. Nobody uses the well as there are taps in everybody's house now.

The following are some statements regarding step wells or baolis:

I. There is a traditional system of water storage and conservation.

II. They were used as a community resource.

III. They are found/constructed mainly in rain-parched states.

IV. They contain only contaminated water.

Which of the above statements(s) is/are correct?

Identify the correct statement(s):

I. The freshwater stored in the ground is less than that present in the rivers and lakes of the world.

II. Water shortage is a problem faced by people only in rural areas.

Ill. Water from rivers is the only source for irrigation in the fields.

IV. Rain is the ultimate source of water.

If we add a handful of garden soil to a beaker filled three-quarters with water, stir the contents with a stick to dissolve the soil, and then let it stand undisturbed for some time, we observe different layers. The order of these layers from the bottom to the top is:

Cereals such as wheat and gram are grown in an area. The soil of this area must be: