Important Very Short Answer Science Questions For Competitive Exams
Jaswinder
Singh (Lect In Physics)
Important Very Short Answer Science Questions For Competitive Exams
1. Give example of a non metal which is good conductor
of electricity.
( Graphite)
2.
Write
full form of ISRO. (Indian Space Research Organization)
3.
Write
full form of DNA. (Deoxyribonucleic acid)
4.
Write full form of RNA.( Ribonucleic Acid)
5.
Write
molecular formula of butane. ( C4H10)
6.
Write molecular formula of ethene. (C2H4)
7.
Write molecular formula of propane. (C3H8)
8.
How
many single covalent bond present in ethane? (Seven)
9.
Draw
the structure of Propanal.
10.
Write
Chemical name and formula of Lime Stone.
(Formula CaCO3 Chemical name-Calcium carbonate)
11.
Write
the name of respiratory organ of fish. (Gills)
12.
Write
mirror formula with help of symbols.
1/f=1/v+1/u
13.
Complete
the equation
H2S2O7
+ H2O ---------> (2H2SO4)
14.
Name
the Universal Donor Blood group in Human beings. ( O Group )
15.
Give
example of a non metal which has lustre. (Carbon/Iodine)
16.
What
is the reflection of light?
Reflection is
the phenomenon of change in the path of light without change in medium.
17.
What
is the refraction of light?
Refraction of light refers to the change in direction of a
ray of light when it travels from one medium to another.
18.
Find
the power of a concave lens of focal length 2 metres.
P=1/f=1/2 = -0.5D
(power of concave lens is negative)
19.
How
do atomic size and metallic character change in a group of Modern Periodic
table on going top to bottom.
( Both are
increase)
20.
What
is a Catalyst?
A substance that increases the rate of a chemical reaction
without itself undergoing any permanent chemical change.
21.
With which Lens is Myopia corrected ?
Concave lens
22.
Define
an Autotrophic Nutrition.
Autotrophic nutrition is the process of an organism being
able to create/produce its own food. An organism capable of synthesizing its own
food from inorganic substances, using light or chemical energy. Green plants,
algae, and certain bacteria are autotrophs.
23.
Write
the constituents of Brass.
( Brass is made up of copper and zinc )
24.
To
which galaxy does our solar system belong?
(Milky way)
25.
Complete
the chemical equation
2CH3COOH
+ 2Na --------------> (2CH3COONa + H2)
26.
How
food synthesized in leaves is carried to other parts of plant? (Through
Phloem Tissue)
27.
What
is the focal length of a plane mirror?
Infinty
28.
What
is the pH value of pure water ?
(Seven, 7)
29.
What
are the components of the transport system in highly organised plants?
(Xylem and Phloem)
30.
How
does the transport of water and minerals take place in such plants? (Through Xylem Tissue)
31.
Why
should curd and sour substances not be kept in brass and copper vessels?
When kept in copper or brass vessels, curd(and other acidic food items) reacts with copper and forms toxic compounds
which may be unfit for human consumption, and may cause food poisoning
32.
Name
any two Phytohormones.
(Auxin And
Gibberellins)
33.
What
kind of mirror is used in vehicles to see the traffic on the rear side? Convex Mirror
34.
What
is an Exothermic reaction?
A chemical
reaction in which amount of energy is released in form of heat.
35.
What
is an Endothermic reaction?
An endothermic process is any
process which requires or absorbs energy from its surroundings,
usually in the form of heat
36.
Three
resistances of two ohm (2Ω) each are connected in series. Find the combined
resistance.
R=R1+R2+R3=2+2+2=6
ohm
37.
Complete
the equations
CH3COOH
+ C2H5OH ----------------------> CH3COOC2H5+H2O
C2H5OH
+ O2 -----------------> 2CO2+3H2O
38.
Write
any four external factors that affect photosynthesis.
Light, carbon dioxide, water, temperature,
oxygen
39.
Write
symbols for Battery, Key or Switch, Ammeter and Resistance.
40.
How
is plaster of Paris [ CaSO4 ½ H2O] prepared.
When gypsum is
heated at 373k, plaster of paris is formed.
2(CaSO4.2H2O)---> 2(CaSO4.½H2O)+3H2O
41.
Define
Power of a lens and write its unit.
Ability
of lens to converge or diverge the light
,and is equal to the reciprocal of focal length expressed in metres. P=1/f(m).
Unit are dioptre(D)
42.
Write
names and formulae of first four members of alkane series .
CH4,
C2H6, C3H8, C4H10
43.
Write
physical and chemical properties of
metals.
Metals are dense, shiny, good conductors of heat
and electricity, and easily lose electrons in chemical reactions.
44.
What
are parasites? Give two examples .
Organism which
depends entirely for nutrition on other organism(host). Examples ticks , worms,
plasmodium
45.
What
is long-sightedness? How is it corrected?
A
person with this defect can see distant objects but cannot see near objects. It
can be corrected by using convex lens.
46.
What
is short-sightedness? How is it corrected?
A person with
this defect can see near objects but
cannot see distant objects. It can be corrected by using concave lens.
47.
Write
the constituents of German silver and Stainless steel.
German silver:
Cu+Zn+Ni Stainless
steel: Fe+Cr+Ni
48.
Write
characteristics of magnetic field lines.
Magnetic field
lines are closed loops which start from north pole and goes to south Pole
outside the magnet and from south to North Pole inside the magnet. Magnetic
field lines never intersect each other. Region where concentration of field
lines is more, the strength of magnetic field is high in that region and
vice-versa.
49.
Write
two functions of blood.
It supplies oxygen
to cells and tissues. It removes carbon dioxide, urea and lactic acid
(waste products) .It regulates our acidity (pH) levels and body temperature. Its white blood cells have antibodies
which defend us from infection.
50.
Write
one function each of ciliary muscles and optic nerves of human eye?
Ciliary muscles- it holds the eye-lens and help in
change its focal length.
Optic nerves- its carries information from retina to
brain
51.
Write
any two measures to prevent rusting of Iron.
Oiling, painting,
greasing, galvanisation, electroplating
By
these methods, the surface becomes water proof and the moisture and oxygen
present in the air cannot come into direct contact with iron.
52.
What do you mean by soil erosion? Write
its two causes.
Soil erosion is the displacement of the upper layer of fertile,
mineral rich soil.
Agents -water and
wind.
53.
Why does the colour of sky appears blue?
Blue light is scattered in all
directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than
other colors because
it travels as shorter, smaller waves.
54.
What are decomposers?
Decomposers are organisms that break down dead or decaying
organisms, and in doing so, they carry out the natural process of decomposition.
55.
What is the role of decomposers in the
ecosystem?
If
they weren't in the ecosystem, the plants would not get essential nutrients, and dead
matter/waste would pile
up.
56.
Write ohm ‘s law.
(V=IR)
57.
What is conductor of electricity? Give two examples.
A conductor is any piece of
material that easily allows heat or electricity to pass through it. copper,
aluminum, gold, and silver.
58.
What is insulator of electricity? Give two examples.
A
material that does not easily transmit energy,such as electric current or heat
is called insulators glass, plastic, rubber, and wood.
59.
Give two examples of semiconductors.
Silicon and Germanium
60.
What are fossils?
Fossils are the remains
of plants and animals that have been preserved within the Earth's crust/ sedimentary
rocks.
61.
Write three difference between aerobic
and Anaerobic respiration.
Aerboic
respiration requires oxygen wheras anaerboic respiration does not. More energy
is generated in aerobic respiration. Carbon dioxide and water are products of
aerobic respiration, whereas lactic acid is the end product of anaerobic
respiration.
62.
Give one example of each of the following.
Combination
reaction, 2 H2(g)
+ O2(g) → 2 H2O(ℓ)
Decomposition
reaction, 2NaHCO3(s)
→ Na2CO3(s) + CO2(g) + H2O(ℓ)
Displacement
reaction, Fe+CuSO4 → FeSO4+Cu
Double
displacement reaction. AgNO3+NaCl→ AgCl+NaNO3
63.
What is Fleming’s Left hand rule?
64.
What is Fleming’s Right hand rule?
65.
Which gas is produced during the
reaction of sodium carbonate and dil HCL?
HCl is an acid and
it reacts with the metal carbonate Na2CO3 to give CO2(carbon dioxide) , H2O and
NaCl ( sodium chloride).
66.
How does the colour of solution change
when iron nails kept in copper sulphate solution?
When Iron nail (Ferrum)
is dipped in Copper sulphate (CuSO4) there takes reaction between
them and copper sulphate change its color from blue to light green.
67.
Write Mendeleev ‘s Periodic law of
classification of elements.
In
1869, Mendeleev classified the
then known 56 elements on
the basis of their
physical and chemical properties in the increasing order of the atomic masses,
in the form of a table.
68.
What do fossils tell us about the
process of evolution?
Fossils areremains or impressions of organisms that lived
in the remote past. Fossils provide
the evidence that the present animal have originated from previously existing
ones through the process of
continuous evolution.
69.
Why is series arrangement not used in
domestic circuits?
In series arrangement same current
will flow through all the appliances, which is not required. Total
resistance of domestic circuit will be sum of the resistance of all appliances
and hence current drawn by the circuit will be less. We cannot use
independent on/off switches with individual appliances.
70.
What is the
important function of presence of ozone in earth’s atmosphere?
Ozone is made up of three
atoms of oxygen. It protects from
harmful ultraviolet (UV) rays from the Sun. It helps to
maintain heat balance on earth.
71.
What is the
function of retina in human eye?
The purpose of the
retina is to receive light that the lens has focused, convert the light into
neural signals, and send these signals on to the brain for visual recognition.
72.
Name the
pigment present in plants, which can absorb solar energy.
Chlorophyll
73.
What are the raw materials for
photosynthesis?
Photosynthesis
requires carbon dioxide, sunlight,
water and chlorophyll as its basic raw
materials.
74.
Name the device which is used to produce
electric current.
(Generator)
75.
Name a metal which is liquid at room
temperature.
(Mercury)
76.
How is hypermetropia corrected?
(using convex lens)
77.
Which part of brain maintain posture and
equilibrium of body? (Cerebellum)
78.
Complete
1KWH=................. J.
1 watt=1 joule/1 sec
1KW=1000J/1 sec=1000J *1 hour/1 sec
1KWH=1000J *3600 sec/ 1 sec= 3.6
*106 J
79.
What is the function of Xylem in plants?
(Transport of water)
80.
What is the chemical name of Baking
Soda?
Sodium bicarbonate,
NaHCO3. (Sodium Hydrogen Carbonate)
81.
At the time of short circuit, what is
the magnitude of current in the circuit?
(Increases heavily)
82.
Write molecular formula of Bromoethane.
CH3CH2Br
83.
Write the formula of electric power.
(P=VI=I2R=V2/R)
84.
Three resistors 2 ohm, 3 ohm, 5 ohm are
connected in series. What is the net resistance?
R=R1+R2+R3=2+3+5=10
ohm
85.
Which acid is present in Ant Sting?
(Methanoic
acid)
86.
What is the least distance of distinct
vision of human eye?
(25
cm)
87.
What is Pollination?
Pollination is transfer of pollen
grains from the anther to the stigma of a flower.
88.
What is the functional group of butanone?
(Ketone group)
89.
What is the functional group of butanal?
( Aldehyde Group)
90.
Write the formula of rust.
Iron + Water + Oxygen =
Rust. (The chemical formula
for rust is Fe2O3.nH2O)
91.
What is hemodialysis ?
It is a method of method of
removing waste products and extra fluid, which build up in the blood when the
kidneys are no longer able to function properly.
92.
Which is the longest gland in human
body?
Liver
93.
What part of the brain is responsible for reflex actions?
In
a reflex action, the spinal
cord along with the brain stem
is responsible for the
reflex movements.
94.
What are male and female part of flower ?
The main flower
parts are the male
part called the stamen and the female part called the pistil.
95.
Find the focal length of a convex mirror
whose radius of curvature is 16 cm.
R=2f, f=R/2, f=16/2=8 cm.
96.
How do metallic character change in a
period moving left to right in modern periodic table.
(Decreases)
97.
What is an alloy?
Mixture of two or more metals or a
metal and a non metal.
Examples Brass, Bronze
98.
Name the basic filtration unit in the
kidney.
(Nephrons)
99.
What is synapse?
A
junction between two nerve cells, which transfer electric activity
(information) from one cell to another.
100.
What is the velocity of light in vacuum?
The velocity of light in vacuum is
3*108 m/s
101.
What is the SI unit of power?
Watt
102.
An electric bulb is rated 220 V and 100
W. When it is operated on 110 V, what will be
the power consumed?
P=V2/R
If V=220V we have
100 W = 2202/R
R = 2202/100 Ω = 484 Ω. This is the resistance of the bulb.
When V = 110 V, power consumed = V2/R = 1102 /484 = 25 W.
If V=220V we have
100 W = 2202/R
R = 2202/100 Ω = 484 Ω. This is the resistance of the bulb.
When V = 110 V, power consumed = V2/R = 1102 /484 = 25 W.
103.
No matter how far you stand from a
mirror,your image appears erect. What will be the nature of image?
Either plane or convex
104.
A doctor has prescribed a
corrective lens of power +1.5 D. Find the focal length of the lens.Is the
prescribed lens converging or diverging?
Power
of lens= 1/focal length
focal
length = 1/power of lens=1/1.5=0.6667 m
Since
the focal length is positive, the prescribed lens is convex and is converging
lens.
105.
What is gangue?
Impurities
of sand and rocky material present in an ore is called gangue
106.
Name a metal which is preserve in kerosene?
Sodium
107.
The element X has electronic configuration 2,8,8,2.It belongs to
which group and period of periodic table?
X = 2,8,8,2
(a) Since it has 4 shells, it belongs to 4th period.
(b) Since it has 2 valence electrons, it belongs to group 2.
The element X is actually Calcium (Ca).
(a) Since it has 4 shells, it belongs to 4th period.
(b) Since it has 2 valence electrons, it belongs to group 2.
The element X is actually Calcium (Ca).
108.
Where fertilization does take place in human beings?
Fallopian
tube
109.
What are 3 R’s to save the environment?
Reduce,
reuse and recycle
110.
The ability of a cell to divide into several cells during
reproduction in plasmodium is called?
Multiple
fission
111.
At what temperature Plaster of paris is prepared by heating
gypsum ?
373 K
112.
What is the name and chemical formula of the main product formed
by heating baking soda?
Sodium carbonate (Na2CO3)
113.
If one of the metal in an alloy is mercury,then what it is called?
Amalgam
114.
What happens when dilute hydrochloric acid is added to iron
powder?
Hydrogen gas and and iron chloride.
115.
The power plant which converts the potential energy of falling
water into electricity is called?
Hydropower
plant
116.
How many covalent bonds in ethane?
7 Covalent bond
117.
Name the chamber of heart which receives deoxygenated blood from
vena cave?
Right
ventricle receives
118.
Where an object should be placed in front of a convex lens to get
a real image of the size of the object?
At
twice the focal length
119.
Which phenomenon is related to twinkling of stars?
Atmospheric
Refraction
120.
While cooking if the bottom of the vessel is blackened on the
outside, what it means?
The fuel is not burning completely
121.
Is the flow of energy in an ecosystem is unidirectional?
The flow of energy in the ecosystem is unidirectional.
122.
Three elements B,Si and Ge are called?
Metalloids
123.
What anther contains?
Pollen grains
124.
Give an example of homologous organs?
The arm of a human, the wing of a bird or a bat, the leg of a
dog and the flipper of a dolphin or whale are homologous structures.
125.
Fe2O3+2Al----à Al2O3+2Fe.This chemical reaction is example
of ?
Displacement
reaction
JASWINDER
SINGH
LECURER IN
PHYSICS
EMAIL
ID-physsrsms@gmail.com
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