Monday, 14 June 2021

KSEEB - Science Multiple Choice Questions Based Model Question Paper - 01 Answer with Explanation

SCIENCE

41. A device used to change the resistance in an electric circuit is 

A. ammeter      B. rheostat     C. galvanometer     D. voltmeter 

Ans: B. rheostat 

Solution:

In an electric circuita device called rheostat is often used to change the resistance in the circuit.

42. In Fleming’s left hand rule middle finger indicates the direction of the 

 A. magnetic field                B. electric current induced in conductor 

C. electric current                D. movement of the conductor 

Ans: C. electric current  

Solution:

Fleming’s left hand rule: The forefinger indicates the direction of the magnetic field; the middle finger indicates the direction of the current and the thumb represents the direction of the motion.

43. A doctor prescribes a corrective lens of power ‒0.5D to a person. The focal length of lens and the type is 
 A. ‒2m and concave lens                      B. +2m and convex lens 
 C. +2m and concave lens                      D. ‒2m and convex lens

Ans:  A. ‒2m and concave lens   

Solution:

Power = 1/f

-0.5 = 1/f

f = -1/0.5

f = -2m

f = -200cm

since focal length is negative, lens is concave (diverging)

44. The nature and the size of the image formed when the object is kept between the principal focus ‘F1 ’ and optical centre ‘O’ of a convex lens is 

A. virtual, erect and enlarged                        B. real, inverted and small size 

C. virtual, inverted and small size                 D. real, inverted and enlarged

Ans:  A. virtual, erect and enlarged   

Solution:


45. The potential difference between the terminals of electric heater is 60V, when it draws a current of 4A from the source. The resistance of electric heater coil is 

 A. 15Ω        B. 240Ω          C. 24Ω             D. 64Ω

Ans:  A. 15Ω

Solution:

Given :
Potential Difference of heater = 60v
current I=4A

Resistance =R?
By Ohm's law :

V=IR
R=V/R
=60/4=15 ohms

46. The diameter of the circular outline of a spherical lens is 

A. optical centre        B. centre of curvature 

C. operture                 D. principal axis

Ans:  C. operture   

Solution: 

 diameter of the circular outline of a spherical lens is called  aperture


47. The inner wall of the solar cooker is painted black because this 

 A. reflects light                           B. absorbs more heat 

C. prevents from rusting              D. converges solar radiations

Ans:  B. absorbs more heat 

Solution: 

 inside the surface of a solar cooker it is painted black in colour because Black surfaces are a good conductor of radiation which absorbs more heat.

48. The function of electric generator is, it 

A. reverses the direction of the current 
B. converts electrical energy into mechanical energy 
C. detects the presence of electric current in circuit 
D. converts mechanical energy into electrical energy

Ans: D. converts mechanical energy into electrical energy

Solution: 

Electric generator, also called dynamo, any machine that converts mechanical energy to electricity for transmission and distribution over power lines to domestic, commercial, and industrial customers. 

49. The resistance of a conductor does NOT depend on 

A. length of conductor        B. area of cross section of conductor 

C. magnetic nature              D. nature of the material

Ans: C. magnetic nature     

Solution:

the resistance of a conductor depends on its length, thickness (i.e. its cross sectional area) and temperature of the conductor

50. D.C. generator works on the principle of 

 A. electromagnetic induction               B. magnetic effect of electric current 

 C. heating effect of electric current    D. chemical effect of electric current

Ans:  A. electromagnetic induction      

Solution:

DC generator operates on the principle of Faraday's laws of electromagnetic induction. According to Faraday's law, whenever a conductor is placed in a fluctuating magnetic field (or when a conductor is moved in a magnetic field) an EMF is induced in the conductor.

51. ‘WATT’ is an SI unit of 

A. electric current                              B. electric charge 

 C. electric potential difference    D. electric power 

Ans:  D. electric power 

Solution:

52. Observe the given table 

Good conductor of electricity among these material is 

A. K              B. L             C. N                D. M

Ans:   B. L 

53. One of the properties of biogas 

A. Its heating capacity is high      B. Leaves residue like ash 

C. It burns with smoke                   D. Its heating capacity is low

Ans:  A. Its heating capacity is high  

Solution:

Biogas is the mixture of gases produced by the breakdown of organic matter in the absence of oxygen (anaerobically), primarily consisting of methane and carbon dioxide. Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste.

  • Biogas don't pollute the environment. 
  • Its heating capacity is high
  • It is renewable source of energy.
  • It reduces soil, water and air pollution.
  • It produces organic manure as byproduct.
  • As it is a low-cost method to produce energy, so it is economically friendly as well.
54. Object distance and image distance of a lens are ‒60 cm and ‒20 cm respectively, then the magnification of lens will be 

 A. ‒ 0.33           B. + 3.0            C. + 0.33            D. + 4.0

Ans:  C. + 0.33

Solution: 

u= -60 cm

v= 20 cm

Mafnification Formula :- M=v/u

M= -20cm/-60cm

M= 1/3

M=0.33

So, the correcet answer is option C +0.33..

55. The process used to convert metal carbonate ores into their oxides is : 

A. roasting      B. reduction       C. electrolysis       D. calcination

Ans:   D. calcination

Solution: 

carbonate ore is converted into oxide by calcination whereas a sulphide ore is converted into oxide by roasting.

56. The correct group of saturated hydrocarbon 

A. CH4 , C2 H4 , C3 H4                B. C2 H6 , C3 H8 , C4 H10 

C. C2 H2 , C2 H6 , CH4                 D. C2 H2 , C3 H6 , C4 H6

Ans:   B. C2 H6 , C3 H8 , C4 H10 

Solution: 

Saturated Hydrocarbons: contain only carbon- carbon single bonds. 

Unsaturated Hydrocarbons: contain carbon- carbon double or triple bonds 

57. The atomic number of an element ‘X’ is 11 and the atomic number of ‘Y’ is 17. Then the type of bond formed between these two elements 

A. hydrogen bond        B. covalent bond    

C. ionic bond                 D. metallic bond

Ans:  C. ionic bond  

Solution: 

The electronic configuration of element X(Z = 11) is Na = 2, 8, 1
The electronic configuration of element Y(Z = 17) is Cl = 2, 8, 7
The bond form will be of ionic nature. atom of X is Na will transfer 1 electron each to atoms of Y is Cl.
The formula of the compound is : NaCl

58. As the pH value of a solution decreases 

A. number of OH‒ ions increases 

B. number of H+ ions increases 

C. number of H+ ions decreases 

D. equal number of OH‒ and H+ ions

Ans:  B. number of H+ ions increases 

Solution: 

pH is the scale used to determine the concentration of hydrogen ions in solution. The scale ranges from 0−14 with 7 being the neutral value. Less than 7 is acidic and more than 7 is basic. Hence, the pH value increases with decrease in hydrogen ion concentration

59. The functional group present in the carbon compound  is 




A. aldehyde        B. alcohol         C. ketone        D. carboxylic acid

Ans:  D. carboxylic acid

Solution: 

Functional groups are the atoms or group of atoms attached to a hydrocarbon chain which changes the property of parent hydroarbon chain .


60. The atomic number of an element is 20. In the modern periodic table this element belongs to the period 

A. 4              B.  8              C. 2             D. 3

Ans:  A. 4

Solution: 

In the modern Periodic table this element belongs to group 2 and period 7.

This can be identified by its atomic no. and its electronic configuration.

As the electronic configuration of 20 will be (2,8,8,2) its valency is 2 and thus it belongs to group 2 and the no. of shells present are 4 n therefore it belongs to period 4.

As the elements placed towards the right-side or present in the s-block are metals.

therefore this element is a metal.

61.  The number of single bonds present in the structure of a cyclohexane molecule 

A. 12             B. 18            C. 24            D. 6

Ans:   B. 18  

Solution:


62. In modern periodic table as we move down a group. The atomic size of the elements
 
A. decreases            B. does not change 

C. increases             D. first increases and then decreases

Ans:   C. increases

Solution: 

On moving down the group, from top to bottom, the atomic size increases. This is because with increase in the atomic number, extra shells of electrons are added.

63. Observe the following chemical reactions 

Fe + CuSO4 → FeSO4 + Cu 

Zn + FeSO4 → ZnSO4 + Fe 

The decreasing order of reactivity of metals in the above reactions is 

A. Zn > Fe > Cu        B. Fe > Cu > Zn 

C. Zn > Cu > Fe         D. Cu > Fe > Zn

Ans:  A. Zn > Fe > Cu 

Solution: 


64. The gas liberated when dilute sulphuric acid reacts with zinc granules 

A. Sulphur dioxide       B. Carbon dioxide 

C. Nitrogen                     D. Hydrogen

Ans: D. Hydrogen

Solution: 

When dilute sulphuric acid is poured on zinc granules, then zinc being more reactive than hydrogen displaces it from the acid and forms zinc sulphate and hydrogen gas.

Zn + H2SO4 → ZnSO4 + H2

Hydrogen is a combustible gas and burns with a popping sound. This can be observed when a match stick which is burnt is bought ear to the test tube.

65. NaOH + HCl → NaCl + H2 O. This chemical reaction is an example of 

A. neutralization reaction     B. substitution reaction 

C. addition reaction                D. combustion reaction

Ans:  A. neutralization reaction

Solution: 

The neutralization reaction is the one in which an acid reacts with an equimolar amount of base to give salt and water. In neutralization reactions, the H+ of the acid combines with OH− ions of the base to form water and other reactants form the specific salt. The neutralization reaction has a pH of 7.

66. The molecular formula of benzene is 

A. C5 H12       B. C6 H12        C. C6 H6              D. C6 H10

Ans:  C. C6 H6

Solution: 

67. The process that helps in the absorption of upward movement of water and minerals dissolved in it from roots to the leaves in plants 

A. Respiration              B. Transpiration 

C. Photosynthesis       D. Translocation

Ans:   B. Transpiration 

Solution:

The continuous evaporation of water (or transpiration) from the cells of a leaf crates a kind of suction which pulls up water through the xylem vessles. Thus, transpiration helps in the upward movement of water and dissolved minerals from the roots to the leaves through the stem.

68. The correct pathway of oxygenated blood coming from lungs to the heart in the human body 
 A. Pulmonary arteries → Right ventricle → Right atrium 
 B. Pulmonary arteries → Right atrium → Right ventricle 
 C. Pulmonary veins → Left ventricle → Left atrium 
 D. Pulmonary veins → Left atrium → Left ventricle

Ans:   D. Pulmonary veins → Left atrium → Left ventricle

Solution:


69. The hormone that regulates carbohydrate, protein and fat metabolism in the human body is 
A. Testosterone          B. Adrenaline

C. Thyroxin                  D. Insulin

Ans:   C. Thyroxin

Solution:

Testosterone is the male sex hormone that is made in the testicles. During puberty (in the teen years), testosterone helps boys develop male features like body and facial hair, deeper voice, and muscle strength.

The adrenal glands are endocrine glands that are responsible for producing important hormones required for bodily functions. Adrenaline is also known as a fight hormone. 

The hormone that regulates carbohydrate, protein and fat metabolism in the human body is Thyroxin

Insulin reduces the blood glucose levels immediately by increasing the transport of glucose in adipose tissue, skeletal muscle cells and liver cells. Insulin stimulates the uptake of the glucose in these cells from the blood.

70. The mismatched pair among the following 

 A. Adrenaline → Pituitary gland

 B. Testosterone → Testes 

 C. Insulin → Pancreas

 D. Thyroxin → Thyroid gland

Ans:   A. Adrenaline → Pituitary gland

Solution: 

The adrenal glands are located at the top of each kidney. They are responsible for producing many hormones, including aldosterone, cortisol, adrenaline, and noradrenaline. Adrenal glands are controlled by another gland called the pituitary gland.

71. The part of human brain responsible for precision of voluntary actions and maintaining the posture and balance of the body 

A. pons                            B. cerebrum 

C. hypothalamus          D. cerebellum

Ans:    D. cerebellum

Solution: 

The pons is the primary structure of the brain stem present between the midbrain and medulla oblongata.  The main functions of the pons include: Controlling sleep cycles.

The cerebrum is responsible for thinking, intelligence, consciousness and memory. 

Hypothalamus main function is maintaining the body’s internal balance- homeostasis.

Cerebellum is the part of human brain responsible for precision of voluntary actions and maintaining the posture and balance of the body 

72. A pathogen that causes gonorrhoea and syphilis transmitted through sexual contact : 

A. Protozoa          B. Bacteria          C. Virus          D. Fungus

Ans:  B. Bacteria

Solution: 

Gonorrhea is caused by the bacterium Neisseria gonorrhoeae. The gonorrhea bacteria are most often passed from one person to another during sexual contact

syphilis is caused by the bacterium Treponema pallidum. The syphilis bacteria are most often passed from one person to another during sexual contact.

73. The correct sequence found in the process of sexual reproduction in flower is 

A. pollination, fertilization, embryo, seed 

B. seed, embryo, fertilization, pollination 

C. embryo, seed, pollination, fertilization 

D. pollination, fertilization, seed, embryo

Ans:  A. pollination, fertilization, embryo, seed 

74. The part of the plant seed that grows and develops into root on germination 

A. Cotyledon        B. Endosperm           C. Radicle         D. Seed Coat

Ans:  C. Radicle  

Solution:

The radicle is the first part of a seedling (a growing plant embryo) to emerge from the seed during the process of germination. The radicle is the embryonic root of the plant, and grows downward in the soil (the shoot emerges from the plumule).


75. If a round green seeded pea plant (RRyy) is crossed with wrinkled yellow seeded pea plant (rrYY). The seeds produced in F1 generation are 

A. Round and green          B. Wrinkled and yellow 

C. Wrinkled and green     D. Round and yellow

Ans: D. Round and yellow

Solution:


76. The experiences of an individual during its life time cannot be passed on to its progony, because they are 

A. inherited traits               B. acquired traits 

C. dominant traits              D. recessive traits 

Ans: B. acquired traits 

Solution:

The experiences of an individual during his/her lifetime cannot be passed on to its progeny because these experiences are an example of acquired traits. These are the changes in the somatic cells which do not take part in reproduction and hence, cannot give rise to inheritance.

77. Analogous organs have 

A. Same structure and same function 

B. Same structure and different functions 

C. Different structures and same function 

D. Different structures and different functions

Ans: C. Different structures and same function 

Solution:

Analogous OrgansOrgans which performs similar function but are different in structure and origin. Example - wings of a bird and wings of an insect. 
Homologous OrganOrgans which have different functions but similar structure and origin.

78. Ozone layer is formed from oxygen at the higher levels of the atmosphere by the action of 

A. X-rays                                  B. Ultra violet - radiations 

C. Infrared radiations         D. Radiowaves

Ans:   B. Ultra violet - radiations 

Solution:

In the stratosphere, ozone is created primarily by ultraviolet radiation. When high-energy ultraviolet rays strike ordinary oxygen molecules (O2), they split the molecule into two single oxygen atoms, known as atomic oxygen. A freed oxygen atom then combines with another oxygen molecule to form a molecule of ozone.


79. A product that can no more be used for the original purpose but use it for some other useful purpose is 

A. recycle        B. reduce         C. reuse       D. repurpose

Ans: D. repurpose

Solution:

Reduce the consumption of various resources wherever possible. For example- we can reduce the consumption of electricity by switching off lights and other appliances when they are not required.

Recycle- There are many items which can be recycled again and again. Recycling is another way of reducing the demand for natural resources. For example- by recycling paper, we reduce the demand for wood and thus, help in saving the forest.

Reuse- Many items can be reused, many times. For example, the old newspaper can be used for packing many items. We can use one side printed sheets for our rough work at home/work.

Repurpose- This means when a product can no more be used for the original purpose, think carefully and use it for some other useful purpose. For example, cracked crockery, or cups with broken handles can be used to grow small plants and as feeding vessels for birds.

Refuse- This means to say No to things people offer you that you don’t need. Refuse to buy products that can harm you and the environment, say no to single-use plastic carry bags.

80. The watershed management 

A. Increases production and income of watershed community 

 B. Increases droughts and floods 

C. Decreases the biodiversity of downstream reservoirs 

D. Increases deforestation

 Ans: Increases production and income of watershed community

Solution:

Watershed is defined as the area of land where all the water drains into a central point, like rivers, lakes or streams.


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