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UPSC Civil services Entrance exams General Studies test # General Science Hydrogen Prepare / Learn

Q1. Most of the s-block elements form dihydrogen compounds which are:

A. covalent

B. highly electropositive

C. neutral

D. highly electronegative

Answer : Option B
Explaination / Solution:

Ionic hydrides are formed when hydrogen molecule reacts with most s-block elements which are highly electropositive in nature. In solid state, the ionic hydrides are crystalline, non-conducting and non-volatile. However, in liquid state it conducts electricity. Ionic hydrides on electrolysis liberate hydrogen gas at the anode.

UPSC Civil services Entrance exams General Studies test # General Science Strategies for Enhancement in Food Production Prepare / Learn

Q2. Which of the following helps in absorption of phosphorus from soil by plants?

A. Frankia

B. Glomus

C. Anabaena

D. Rhizobium

Answer : Option C
Explaination / Solution:

Anabaena is a photoautotrophic algae that generally grows in rice field. It increase the nitrogen in soil along with it also help in absorption of phosphorous from the soil by the plants.

UPSC Civil services Entrance exams General Studies test # General Science Magnetism and Matter Prepare / Learn

Q3.

\vec{H}

=magnetic intensity,

χ

=susceptibility, magnetic moment per unit volume

\vec{M}

equals

A. 2χH⃗

B. χH⃗

C. χ2H⃗

D. πχH⃗

Answer : Option B
Explaination / Solution:
No Explaination.

UPSC Civil services Entrance exams General Studies test # General Science Coordination Compounds Prepare / Learn

Q4. Which of the following pair contains complex salt and double salt respectively?

[C u {(N H_{3})}_{4}] S O_{4}, F e S O_{4} .7 H_{2} O

M g S O_{4} .7 H_{2} O, C u S O_{4}

F e S O_{4}, K_{4} [F e {(C N)}_{6}]

Answer : Option A
Explaination / Solution:

[C u {(N H_{3})}_{4}] S O_{4}

this is complex salt while

K_{2} S O_{4} A l_{2} {(S O_{4})}_{3} .24 H_{2} O

is double salt.

UPSC Civil services Entrance exams General Studies test # General Science Biodiversity and Conservation Prepare / Learn

Q5. Project elephant started in the year:

A. 1992

B. 1990

C. 1993

D. 1982

Answer : Option A
Explaination / Solution:

Project Elephant (PE) was launched by the Government of India in the year 1992 as a Centrally Sponsored Scheme with following objectives:

To protect elephants, their habitat & corridors
To address issues of man-animal conflict
Welfare of captive elephants

UPSC Civil services Entrance exams General Studies test # General Science Gravitation Prepare / Learn

Q6. The acceleration due to gravity at a height h in terms of mass of earth

M_{E}

and radius of the earth

R_{E}

and gravitational constant G is

A. g(h)=ME(RE+h)2

g(h)=GmME(RE+h)2

C.

g(h)=GME(RE+2h)2

D. g(h)=ME(RE+h)2

Answer : Option A
Explaination / Solution:

We know by Newton's law of gravitation, the force on the body of mass m, situated at height h to the surface of the earth of mass ME is given by:

$F = G \frac{M_{e} m}{{(r + h)}^{2}}$ -(1)

we also know F=mass X acceleration( here acceleration is acceleration due to gravity)

$\Rightarrow$ F=mg -(2)

Equating (i) & (ii), we get

$g = G \frac{M_{e}}{{(r + h)}^{2}}$

UPSC Civil services Entrance exams General Studies test # General Science Electrochemistry Prepare / Learn

Q7. Kohlrausch law of independent migration of ions states

A. that limiting molar conductivity of an electrolyte can be represented as the sum of the individual contributions of the anion and cation of the electrolyte

B. none of these

C. that limiting molar conductivity of an electrolyte can be represented as the difference of the individual contributions of the anion and cation of the electrolyte

D. that molar conductivity of an electrolyte can be represented as the sum of the individual contributions of the anion and cation of the electrolyte

Answer : Option A
Explaination / Solution:

Statement of Kohlrausch Law.

UPSC Civil services Entrance exams General Studies test # General Science Electronic Devices Prepare / Learn

Q8. The electron and hole concentration in a semiconductor in thermal equilibrium is given by

A. nenh=2n2i

B. nenh= n2i

C. 2nenh=n2i

D. nenh=n3i

Answer : Option B
Explaination / Solution:

The number of carriers in the conduction and valence band with no externally applied bias is called the equilibrium carrier concentration.

For majority carriers, the equilibrium carrier concentration is equal to the intrinsic carrier concentration plus the number of free carriers added by doping the semiconductor. Under most conditions, the doping of the semiconductor is several orders of magnitude greater than the intrinsic carrier concentration, such that the number of majority carriers is approximately equal to the doping.

At equilibrium, the product of the majority and minority carrier concentration is a constant, and this is mathematically expressed by the Law of Mass Action.

$n_{e} n_{h} = n_{i}^{2}$

Where ni is the intrinsic carrier concentration and neand ph are the electron and hole equilibrium carrier concentrations.

UPSC Civil services Entrance exams General Studies test # General Science Animal Kingdom Prepare / Learn

Q9. Haemocoel is found in

A. Earthworm

B. Hydra

C. Pila

D. Snake

Answer : Option C
Explaination / Solution:

Haemocoel is the main body cavity of invertebrates such as insects. It is also found in pila which does not contain blood circulating system.

UPSC Civil services Entrance exams General Studies test # General Science Forms of Market and Price Determination Prepare / Learn

Q10. In perfect competition, since the firm is a price taker, the ________ curve is straight line

A. Marginal revenue

B. Total cost

C. Total revenue

D. Marginal cost