Tag: evs

Questions Related to evs

The Precambrian red rock indicates the ________________.

evs mud and stones soil - formation and profile soil-nature soil profile

  1. Presence of the free oxygen

  2. Absence of free oxygen

  3. Presence of hydrogen

  4. Presence of water

Show answer
Correct Option: A

The geological age of a rock is determined by.

evs mud and stones soil - formation and profile soil-nature soil profile

  1. The fossil flora and fauna

  2. Chemical composition of the rocks

  3. Radiometric dating

  4. Spectroscopic data

Show answer
Correct Option: A

Humification results in the formation of ............. substance.

evs mud and stones soil - formation and profile soil-nature soil profile

  1. Colloidal and Basic

  2. Acidic and Dark colored

  3. Amorphous and Light colored

  4. Light coloured colloidal

Show answer
Correct Option: B
Explanation:

  • Humification is a process in which organic material decomposes and breaks down. It results in the formation of humus. Humus is a dark-coloured, amorphous and acidic substance. 
  • It occurs in soils and peats. It improves the quality of soil by providing nutrient substances like nitrogen.

Thus, the correct answer is 'Acidic, Dark coloured.'

'X' is an organic substance obtained from the decomposition of plant or animals wastes which provides lots of humus to the soil. Identify the incorrect statements regarding decomposition.

evs mud and stones soil - formation and profile soil-nature soil profile

  1. It makes the soil porous

  2. It reduces the water holding capacity of the soil

  3. it increase the number of friendly microbes

  4. It improves the texture of the soil

Show answer
Correct Option: D
Explanation:

Humus is the dark, organic material formed in the soil when plant and animal matter decays.
It is important as it retains-
1)  Moisture content in the soil.

2) Loosens the soil which allows better aeration and drainage.
3) It encourages the increase of soil organisms which help make nutrients available to plants. 
4) It makes the soil more porous.
5) High humus content increases water holding capacity of the soil.
So, the correct answer is 'It improves the texture of the soil'.

When a small amount of garden soil is put into a glass jar containing water, stirred and allowed to stand for two hours, the layers from top to bottom would be

evs mud and stones soil - formation and profile soil-nature soil profile

  1. Debris, water, sand and clay

  2. Humus, water, clay and sand

  3. Debris, clay, gravel and sand

  4. Humus, clay, gravel and sand

Show answer
Correct Option: B
Explanation:

Soil is comprised of air spaces and organic matter, but mostly mineral particles. There are three kinds of soil minerals, sand, silt and clay. The relative percentage of each of these particles in the soil determines its texture. Sand has the largest soil particles (0.4- to 0.01-inch diameter) and the largest pores between particles. Silt soil particle size is between clay and sand (0.01- to 0.0001-inch diameter). The characteristics of silty soil are similar to those of clay, but are moderated by its larger particle size. Clay soil has the smallest soil particles (less than 0.0001-inch diameter) and the least amount of water and air spaces between particles. Humus is dark, organic material that forms in soil when plant and animal matter decays. The thick brown or black substance that remains after most of the organic litter has decomposed is called as humus. Hence, humus settles at the topmost and sand the lowermost since, its size is maximum.

Match the following.

Column I Column II
I. Sandy soil A. 85% sand + 15% clay or silt
II. Loam soil B. 70% sand + 30% clay or silt
III. Silt C. 50% sand + 50% clay or silt or both
  D. 90% silt + 10% sand
evs mud and stones soil - formation and profile soil-nature soil profile

  1. I-A, II-D, lll-C

  2. I- A, II- B, lll- D

  3. I- A, II- D, lll- B

  4. I- A, II- B, lll- C

  5. I- A, II- C, lll- D

Show answer
Correct Option: E
Explanation:

Sand can refer to a textural class of soil or soil type; i.e., a soil containing more than 85% sand-sized particles (by mass) and 15% clay.

A loamy soil is one that combines sand and clay particles in relatively equal amounts. Loamy soil is ideal for most garden plants because it holds plenty of moisture but also drains well so that sufficient air can reach the roots. Loam is soil composed mostly of sand and silt, and a smaller amount of clay (about 70%-30% concentration, respectively). The soil can be called as silt if its silt content is greater than 90 percent.

Which of the following characteristics is not a function of humus in soil?

evs mud and stones soil - formation and profile soil-nature soil profile

  1. Provides nutrients

  2. Raises pH

  3. Retains moisture

  4. Humus does all of the above in soil

Show answer
Correct Option: B
Explanation:

Explanation: Humus is the end product of broken down (decayed) organic matter. Humus is an essential component of healthy soils that has many great benefits.

Mineral nodules present in ocean which can meet shortage of important soil nutrient are

evs mud and stones soil - formation and profile soil-nature soil profile

  1. Manganese nodules

  2. Phosphorite nodules

  3. Magnesium nodules

  4. All of the above

Show answer
Correct Option: B
Explanation:
  • Phosphorite rocks are spherical concentrations that are randomly distributed along the floor of continental shelves. It contains high amounts of phosphate minerals. 
  • The size of Phosphorite nodules can range up to several tens of centimetres.
  • Hence Mineral nodules present in the ocean which can meet the shortage of important soil nutrient are Phosphorite nodules.
  • So, the correct answer is 'Phosphorite nodules'.

State whether true or false.
In a completely dark room, if you hold up a mirror in front of you, you will still see a reflection of yourself in the mirror.

evs light, shadows and images what makes things visible nature and sources of light light travels in straight line

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Since there is no source of light in the room, so reflection can't be seen in the mirror. Th given statement is thus false.

State whether true or false.
The moon is luminous body.

evs light, shadows and images what makes things visible nature and sources of light light travels in straight line

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Moon reflects the light of sun and not its own light. So, moon is a non-luminous body.