Note: Only MCQs and Short answer questions have been published in this blog. The Long answer questions have been added into the notes of respective units.
Light
Q. A ray of light goes from water into air. Will it bend towards normal?
Ans: No,
the ray of light will bend away from the normal.
Q. Name
the mirror which can give an erect and enlarged image of an object.
Ans: The
Concave mirror can give erect and enlarged image of an object when it is placed
between Focus and Pole.
Q. Which
type of lens has positive power?
Ans: Convex
lens has positive power as its focus lies towards the right side of lens.
Q. A
diverging lens has a focal length of 0.10 m. What is its Power?
Ans: Power of
Lens= 1/Focal length.
= 1/-0.10
= - 100/10
= - 10
Q. The
power of lens is + 2.5 D, what kind of lens it is and what is its focal length?
Ans:
Since the power of lens is +, the lens should be Convex.
Its focal
length will be given as
1/F = 2.5
F
= 1/ 2.5
F = 0.40 m
Q. A
concave lens produces an image 20 cm from the lens of an object placed 30 cm
from the lens. Find the focal length of the lens.
Ans: Here, V = - 20
, U = -30
We have,
1/V – 1/U
= 1/F
1/-20 – 1/-30 = 1/F
1/-20 +
1/30 = 1/F
-3 + 2
= 1/F
60
-1/60 = 1/F
F = -
60
Q. Which
type of mirror could be used as a shaving mirror?
Ans: The
Concave mirror is used as a shaving mirror as it produces enlarged and erect
image when the object is between Focus and Pole.
Q. Name
the phenomenon due to which swimming pool appears less deep that it really is.
Ans: The Swimming
pool appears less deep due to the phenomenon of Refraction.
Q. Which
type of lens are thinner in the middle than at the edges?
Ans:
Concave Lens are thinner in the middle than the edges.
Q. Name
the mirror which gives an erect and diminished image of an object.
Ans: Convex
mirror gives erect and diminished image of an object.
Q. A ray
of light passes from air to glass, Is the angle of refraction greater or less
than angle of Incidence?
Ans: When a
ray of light passes from air to the glass, it will bend towards the normal.
Hence, the angle of refraction is less than the angle of Incidence.
Q. Which
type of lens is thicker in middle than at the edges?
Ans: Convex
lens is thick in the middle than at the edges.
Human eye and the colourful world
Q. The colored
light having maximum speed in the glass prism is:
A.
Blue B. Green C. Violet D. Yellow
Ans: Yellow
Q Which of
the following color of white light has the least wave length?
a. Red b. Orange
c. Violet d. Blue
ans: c.
Violet
Q. There
are two types of light sensitive cells in the human eye:
i. Where
are they found? ii. What is each
type called?
Ans: The
two types of light sensitive cells in human eye are found inside the Retina.
ii. They
are called as Rod cells and Cone cells.
Q. Make
two diagrams to explain refraction and dispersion
Ans:
Q. Why
do stars seem higher than they actually are?
Ans: The
stars seem higher than they actually are is due to atmospheric refraction.
Q. Why
do stars twinkle in a clear night?
Ans: The
stars twinkle in a clear night due to atmospheric refraction.
Q. What
is atmospheric refraction? Give its causes.
Ans: Atmospheric
refraction is defined as the refraction of light caused by the
earth's atmosphere. Atmospheric Refraction occurs because the different layers
of earth's atmosphere vary in terms of optical densities.
Q. A
beam of white light falling on the glass prism cannot be:
a.
Deviated b. Dispersed c. Focused
d. Refracted
Ans: c.
Focused
Electricity
Q. At
the time of short circuit, what happens to the current?
Ans: At the
time of short circuit, the current increases multifold. It may cause fire.
Q. The
heating elements of electrical heating devices are usually made of:
a.
Tungsten b. Bronze c. Nichrome d. Argon
Ans: c.
Nichrome
Q. Which
of the following characteristics is not suitable for a fuse wire?
a. Thin and
Short b. Thick and short c. Low melting point d. Higher resistance
Ans: b.
Thick and Short
Q. The
heat produced by passing an electric current through fixed resistor is
proportional to the square of :
a.
Resistance b. Current c. Temperature d. Time
Ans: b. Current
Q. If
the current flowing through a fixed resistor is halved, the heat produced in it
will become:
a.
Double b. One half c. One fourth d. Four times
Ans: c. One fourth
Q. An
electric fuse works on the:
A. Chemical
effects of current B. Magnetic
effects of current
C. Lighting
effect of current D. Heating
effect of current
Ans: D.
Heating effect of Current
Q. Two
resistors of resistance 2 ohm and 4 ohm are to be connected to a battery of
e.m.f 6V so as to obtain maximum current flowing. Find the current in this
case.
Ans: The
maximum current will flow in the circuit when there is minimum resistance to
the flow of current.
Therefore,
the resistances shall be connected in parallel.
Here, V = 6
V,
1/R = ½ + ¼
1/R = 2 + 1
4
1/R = ¾
R = 4/3
R = 1.33
Current (I)
= V / R
I
= 6/1.33
I = 4.5 A
Q. Find
the energy transferred by a 100 W electric bulb in 1 minute.
Ans: We
have,
Energy
= Power x Time
Energy = 100 w x 60 s
Energy = 6000 Joules
Q. Of
which substance is the fuse wire made?
Ans: Fuse
wires are made of Nichrome.
Q. In
household circuits, is a fuse wire connected in series or in parallel?
Ans: The
fuse wire is connected in series in a household circuit.
Magnetic Effects of Current
Q. State
Fleming’s left-hand rule.
Ans: Fleming's
left-hand rule is used to find the direction of the force acting on
the current carrying conductor placed in a magnetic field.
It states
that if we arrange our thumb, forefinger and middle finger of the right-hand
perpendicular to each other, then the thumb points towards the direction of the
motion of the conductor relative to the magnetic field, the forefinger points
towards the direction of the magnetic field and the middle finger points
towards the direction of the induced current.
Q. Out
of A.C generator and a D.C generator, which one uses a commutator?
Ans: An D.C
generator uses commutator.
Q. Out
of A.C generator and a D.C generator,
which one uses slip rings?
Ans: An A.C
generator uses Slip rings.
Q. What
is magnetic field? State any two properties of magnetic field lines?
Ans: The magnetic
field is a vector field that describes magnetic influence of the charges and
magnetic materials.
Two properties
of magnetic field lines are:
1. They never
cross each other.
2. They
flow from North to south pole outside the magnet.
Q. What
type of generator is used at power stations?
Ans: A.C
generator is used in power stations.
Q. What
is the principle of electric motor? Name two devices in which electric motor is
used?
Ans: Electric
motor works on the principle of Flemings Left hand rule.
Electric motors are used in water pumps, electric fans, electric mixers etc.
Chemical Reactions and Equations
Q. What
do you mean by exothermic reaction? Give one example
Ans: Exothermic
reaction is a type of reaction in which heat is given out. In other words
energy is produced. E.g
C + O
-------------> CO2
C6H12O6 + 6O2 ------Ã
6CO2 + 6H2O
Q. What
do you mean by Endothermic reaction? Give one example
Ans: Endothermic
reaction is a type of reaction in which heat is absorbed. In other words energy
is needed for reaction to take place. E.g
N2 +
O2 -----------> 2NO
6CO2 + 6 H2O
----Ã
C6H12O6 + O2
Q. What
is balanced chemical equation? Why should chemical equations be balanced?
Ans: A balanced equation is a chemical equation which has equal number of atoms in reactants as well as products. The chemical equation needs to be balanced so that it follows the law of conservation of mass.
Periodic Classification of Elements
Q. The
modern periodic table was prepared by:
A.
Dobereiner B. Bohr C. Mendeleev D. Newlands
Ans: B. Bohr
Q. The
newlands law of octaves for the classification of elements was found to be
applicable only upto the element:
a.
Potassium b. Calcium c. Cobalt d. Phosphorus
Q. The
noble gas having only two electrons in its valence shell is
a.
Argon b. Neon c. Helium d. Krypton
Ans: c.
Helium
Q. In
Mendeleev’s periodic table, gap was not left for one of the following elements.
This element is:
a.
Gallium b. Beryllium c. Germanium d. Scandium
Ans: b. Beryllium
Q. The
electrons present in the valance shell of a noble gas atom can be:
a. 8
only b. 2 only c. 8 or 4
d. 8 or 2
Carbon and its Compounds
Q. Name
the functional group which always occurs at the middle of carbon chain.
Ans: The
Ketone is always present at the middle of carbon chain.
Q. Why
does ethyne burn with a sooty flame?
Ans: When
ethyne is burned in air, it does not get completely oxidised, thereby producing a sooty flame.
Q. What
is the common name of Methanol
Ans: Spirit
or Methyl Alcohol
Q. Name
the product formed when hydrogen is added to ethene.
Ans: When Hydrogen
is added to Ethene, Ethane is formed.
Q. Name
a covalent molecule having a double bond between its atoms.
Ans: Oxygen
(O2)
Q. What
is the common name of Propanone?
Ans: Acetone.
Q. Name
the gas evolved when ethanoic acid is added to sodium carbonate
Ans: When
ethanoic acid is added to Sodium carbonate, Carbon dioxide is formed.
Metals and Non Metals
Q. What
is corrosion? Name any two metals which do not corrode easily.
Ans:
Corrosion is the reaction of metal with the air and moisture.
The two
metals which doesn’t corrode easily are Gold and Silver.
Q. What
are Metals? State two physical properties of Metals.
Ans: A
metal is a material that has lustrous appearance, and conducts electricity and
heat relatively well. Metals are typically ductile and malleable. These
properties are the result of the metallic bond between the atoms or molecules
of the metals.
Acids, Bases and Salts
Q. The
indicators which turn red in acid solution are:
a. Turmeric
and litmus b.
Phenolphthalein and Litmus
c. Litmus and Methyl orange d. Phenolphthalein and methyl orange
Ans: c. Litmus and Methyl orange
Q. The
Property which is common between Vinegar and Curd is:
a. Sweet
taste b. Tasteless c. Bitter taste d. Sour taste
Ans: d. Sour taste
Q. The indicator which produces a pink colour in an alkaline solution is:
a. Methyl
orange b. Turmeric powder c. Phenolphthalein d. Litmus paper
Q. One
of the following is not an organic acid. This is
a. Ethanoic
acid b. Formic acid c. Citic acid d. Carbonic acid
Ans: d.
Carbonic acid
a. They
have sour taste b. They feel
soapy
c. They
turn litmus red d. Their pH is
< 7
Ans: b.
They feel soapy
a.
Five b. Two c. Ten
d. Seven
Ans: c.
Ten
Q. What
are amphoteric oxides? Give two examples
Ans: Amphoteric
oxides are the oxides which have a tendency to react with both acid and base to
form salt and water are known as amphoteric oxides. Examples: Al2O3, ZnO
Q. Bee
stings can be treated with?
A.
Vinegar B. Potassium hydroxide C. Sodium hydrogen carbonate D. Lemon Juice
Q. The
acid produced naturally in our stomach is:
a. Acetic
acid b. Citric acid c. Hydrochloric acid d. Sulphuric acid
Ans: c.
Hydrochloric acid
Life Processes
Q. Do
all the cells use oxygen to produce energy?
Ans: No all
the cells do not use oxygen to produce energy.
Q. Name
the organism that has parasitic mode of nutrition?
Ans:
Ascaris, Tapworm, Lice show parasitic mode of nutrition.
Q. Name
one organism that can live without oxygen?
Ans: Yeast
Q. What
is another name of Food Pipe.
Ans: Oesophagus
Q. In
which part of digestive system is water absorbed?
Ans: Large Intestines.
Q. Name
the process by which plant parts like roots, stem and leaves get oxygen
required for respiration?
Ans: Diffusion
Control and Coordination
Q. Which
of the following helps in maintaining posture and balance of the human body ?
a.
Cerebellum b. Cerebrum c. Medulla d. Pons
Ans: a.
Cerebellum
Q. The
number of pairs of nerves which arise from the spinal cord is :
a. 21 b. 41
c. 31 d. 51
Ans: c.
31
Q. The
spinal cord originates from:
a.
Cerebrum b. Cerebellum c. Medulla d. Pons
Ans: c. Medulla
Q. The
involuntary actions in the body are controlled by:
a. Medulla
in Forebrain B. Medulla in hind
brain
c. Medulla
in Spinal cord D. Medulla in Mid brain
Ans: B.
Medulla in hind brain
a. Mid
brain b. Hind brain c. Fore brain D. Spinal Cord
Reproduction
Q. What
is the other name of sex cells?
Ans: The
sex cells are also called gamates.
Ans: The
female sex cells are called Eggs or Ova
Q. What
are the male sex cells in humans called?
Ans: The
male sex cells in humans are called sperms.
Reason:
The parent body simply breaks up into smaller pieces on maturation
Reason:
Humans have two types of chromosomes: XX and XY
Our Environment
Q. Which
of following constitutes a food chain:
a. Grass,
Wheat and Mango b. Goat, Cow,
elephant
c. Grass,
Goat and Human d. Grass, Fish and
Goat
Q. In a
food chain, the initial organism is usually:
a.
Photosynthetic b. Herbivore c. Saprophytic d. Parasitic
Q. In a
food chain, the third trophic level is always occupied by:
a.
Carnivore b. Decomposers c. Herbivores d. Producers
Ans: a.
Carnivore
Q. One
of the following is not a consumer below:
a.
Giraffe b. Antelope c. Algae
d. Alligator
Q. In a
food chain comprising of snakes, grass, insects and frog, the secondary
consumer is :
a.
Insect b. Snake c. Frog
d. Grass
Management of Natural Resources
Q.
Assertion: Natural resources need to be used carefully.
Reason:
Resources are finite in supply and human population in tremendously increasing.
Ans: Both A
and R are correct and R is right explanation of A
