General Science | General Studies test | UPSC Civil services Entrance exams Online Objective Test

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

Q1. Amount of biomass produced per unit area by green plants is called:

A. Secondary productivity

B. Respiration

C. Primary productivity

D. Tertiary productivity

Answer : Option C
Explaination / Solution:

Primary productivity refers to the degree to which autotrophic organisms (primarily plants and algae) convert energy into organic substances through photosynthesis or chemosynthesis. Since the process of photosynthesis consumes carbon dioxide and produces oxygen, it is of great importance to the environment. Primary productivity refers to the amount of carbon-fixing biomass produced.

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

Q2. Relation between ray and wave front is

A. Rays are parallel to wave front

B. Rays are at acute angle to wave front

C. Rays are tangential to wave front

D. Rays are perpendicular to wave front

Answer : Option D
Explaination / Solution:

Huygens’ construction tells us that the new wavefront is the forward envelope of the secondary waves. When the speed of light is independent of direction, the secondary waves are spherical. The rays are then perpendicular to the wavefronts.

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

Q3. Heavy hydrogen is also called

A. deuterium

B. protium

C. tritium

D. dihydrogen

Answer : Option A
Explaination / Solution:

Deuterium, (D, or 2H), also called heavy hydrogen, isotope of hydrogen with a nucleus consisting of one proton and one neutron, which is double the mass of the nucleus of ordinary hydrogen (one proton). Deuterium has an atomic weight of 2.014.

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

Q4. The method of producing thousands of plants through tissue culture is called

A. Micro propagation

B. Somatic Hybridisation

C. Bio magnification

D. Bio-fortification

Answer : Option A
Explaination / Solution:

The method of producing thousands of plants through tissue culture is called micro propagation. In this method, small part of plant is kept in nutrient medium along with plant hormones.

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

Q5. The coordination number of the central ion may be obtained from

A. The number of ionic bonds formed with the surrounding ions

B. The number of ions of opposite charge immediately surrounding the specific ion

C. None of these

D. The number of coordinate bonds formed with the surrounding ions

Answer : Option D
Explaination / Solution:

Coordination number of the central ion is equal to no. of coordination bonds formed with surrounding ions.

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

Q6. magnetic potential energy Um of Compass needle of known magnetic moment m in a uniform magnetic field field is

A. 2m⃗ .B⃗

B. m⃗ .B⃗

C. 2πm⃗ .B⃗

D. - m⃗ .B⃗

Answer : Option D
Explaination / Solution:
No Explaination.

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

Q7. When we will move away from the equator towards poles, we will find

A. no change in the species diversity

B. a gradual increase in the ecosystem diversity

C. a gradual decrease in the species diversity

D. a gradual increase in the species diversity

Answer : Option C
Explaination / Solution:

When we will move away from the equator towards poles there is a gradual decrease in the species diversity. This is because climatic condition becomes gradually adverse as we move from equator to poles.

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

Q8. Relationship between equilibrium constant of the reaction and standard potential of the cell in which that reaction takes place is

Answer : Option B
Explaination / Solution:

At equilibrium E cell becomes zero .

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

Q9.

The gravitational force on point mass m1 due to point mass m2, m3 & m4 is:

A. the difference of gravitational forces exerted by

m_{2}

m_{3}

and

m_{4}

B. the scalar sum of the gravitational forces exerted by

m_{2}

m_{3}

and

m_{4}

C. the difference of gravitational forces exerted by

m_{4}

m_{3}

and

m_{2}

D. the vector sum of the gravitational forces exerted by

m_{2}

m_{3}

and

m_{4}

Answer : Option D
Explaination / Solution:

According to properties of gravitational force: force between the particles is independent of the presence or absence of other particles; so the principle of superposition is valid i.e. force on a particle due to a number of particles is the resultant of forces due to individual particles i.e.

\vec{F_{1}} + \vec{F_{2}} + \vec{F_{3}} + . . . . . . . . .

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

Q10. The total current in a semiconductor is

A. hole current only

B. the sum of electron and hole currents

C. the difference of electron and hole currents

D. electron current only

Answer : Option B
Explaination / Solution:

Electrons will experience a attractive force from the positive terminal, so they move towards the positive terminal of the battery by carrying the electric current.

Similarly holes will experience a attractive force from the negative terminal, so they moves towards the negative terminal of the battery by carrying the electric current.

Thus, in a semiconductor electric current is carried by both electrons and holes. In intrinsic semiconductor the number of free electrons in conduction band is equal to the number of holes in valence band.

The current caused by electrons and holes is equal in magnitude. The total current in intrinsic semiconductor is the sum of hole and electron current.

Total current = Electron current + Hole current I = $I_{h o l e} + I_{e l e c t r o n}$