A fertile agricultural soil appears dark coloured at the surface as compared to soil one metre down. The reason for colour of top soil is

Monjur Alahi

A fertile agricultural soil appears dark coloured at the surface as compared to soil one metre down. The reason for colour of top soil is
A. more moisture
B. rich in organic matter
C. rich in iron, calcium and magnesium
D. recent formation


0 like 0 dislike
1 views
Share with your friends

1 Answers

Salim Ahmed Kawsar

Call

Correct Answer - B
Dark colour of soil is due to accumulation of leached organic substances and organic matter which serves as a reservoir of nutrients and water in the soil, aids in reducing compacting and surface crusting and increases water infiltration into the soil.

0 like 0 dislike
1 views
Talk Doctor Online in Bissoy App
`Fe^(2+)` does not give prussian blue colour with `K_4[Fe((CN)_6]`, but on its reaction with (X), prussian blue colour appears with the reagent (X) is

Correct Answer - A `MnO_4 H^(+) to[O] : Fe^(2+)overset([O])toFe^(3+)+[Fe(CN)_6]^(4-)to Fe_4[Fe(CN)_6]_3`

2 Answers 1 views
To an astronaut the sky on the moon appears dark because

Correct answer is (b) There is no atmosphere on the surface of the moon The sky appears dark to an astronaut in space because of no atmosphere to undergo no scattering of...

2 Answers 3 views
Assertion: Chloroform is generally stored in dark coloured bottles filled to the brim. Reason: Chloroform reacts with glass in the presence of sun lig

Correct Answer - C Correct reason. Chloroform is oxidised to a poisonous gas phosgene in the presence of sun light and traces of oxygen.

2 Answers 1 views
A base type indicator `B` differs in colour from its conjugate acid.`(BH^(+))` .Acidic form is red in colour while basic form is blue in colour. Human

`:.pOH=pK_(eq)+log((["Acidic form"])/(["Baic form"]))=pK_(eq)+log((["Red"])/([Blue]))` `(pOH)_(blue)=pK_(eq)+log((b)/(a))` and `p(OH)_(red)=pK_(eq)+pK_(eq)+log((c)/(d))` so range `=pH_(blue)` to `pH_(red)=14-pK_(eq)-log((b)/(a))` to `14-pK_(eq)-log((c)/(d))`

2 Answers 1 views
A coin is tossed three times, consider the following events. A : No head appears, B: Exactly one head appears and C: Atleast two appear. Do they form

The sample space of the experiment is `S = {HHH,HHT,HTH,THH,HT T,THT,T TH,T T T}` `A = {T T T}` `B = {HT T, THT, T TH}` `C = {HHT, HTH,...

2 Answers 1 views
A soap flim of thickness `0.3 mu m` appears dark when seen by the refracted light of wavelength `580 nm`. What is the index of refraction of the soap

Correct Answer - 1.45 The path difference is `2mu t`. Now for destructive interface it can be `2mut=(lambda)/(2)` or `(3lambda)/(2)` or `(5lambda)/(2)` and so on……… `mu=(lambda)/(4 t),(3lambda)/(4 t),(5lambda)/(4 t)……..` `=(580xx10^(-9))/(4xx0.3xx10^(-6)) ,...

2 Answers 2 views
Number of six-digit numbers such that any digit that appears in the number appears at least twice, where the digits of each number are from the set `{

Correct Answer - C `(c )` Case I : All six digits alike i.e. `111111`, `222222`……..etc. `=5` ways Case II : `2` alike `+2` other alike. Select any three in `"^(5)C_(3)`...

2 Answers 4 views
The number of `n` digit number formed by using digits `{1,2,3}` such that if `1` appears, it appears even number of times, is

Correct Answer - B `(b)` Required number of numbers `="(n)C_(0)(2)^(n)+"(n)C_(2)(2)^(n-2)+…` We know that `(1+x)^(n)+(x-1)^(n)=2sum_(k=0)^(n)"(n)C_(k)x^(k)` Hence, put `x=2`, get the result `2["^(n)C_(0)(2)^(n)+^(n)C_(2)(2)^(n-2)+^(n)C_(2)(2)^(n-4)+^(n)C_(6)(2)^(n-6)+...]`

2 Answers 1 views
Non-institutional Sources of Agricultural Credit and Institutional Sources of Agricultural Credit.

Non-institutional Sources of Agricultural Credit Institutional Sources of Agricultural Credit (i) It includes money lenders, traders, landlords, commission agents, friends, and relatives, etc. (i) It includes commercial banks, Regional Rural Banks (RRBs), Rural...

2 Answers 2 views
Identify the soil which ranges from red to brown in colour and saline in nature: (a) Red soil (b) Laterite  soil (c) Arid soil (d) Alluvial soil

Answer is : (c) Arid soil

2 Answers 1 views
X