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Sunday 28 November 2021

STD-VI, Electric Current and Circuits, Objective Question-Answers

 

1.  This is used for grinding of wheat-

(a) electric alarm clock

(b) electric flour mill

(c) electric fan

(d) electric oven

 

ANS: electric flour mill

 

2.  Electricity can be generated from _____ sources.

(a) renewable

(b) non-renewable

(c) both renewable and non-renewable

(d) None of these

 

ANS: both renewable and non-renewable

 

3.  Combination of cells form a-

 

ANS: Battery

 

4.  The electric bulb in a torch is kept at the focus of a ______ mirror.

 

ANS: Concave

 

5.  Electric cells produce electricity from ______ stored, and arranged inside them.

 

ANS: Metals and chemicals

Wednesday 24 November 2021

MATH, SIMPLIFICATION

 1.      Simplify the following.

a)      18 + 4 x 6 ÷ 2 – 9

b)      17 x 3 + 81 ÷ 9 – 60

c)      5.3 + 6 x 0.05 – 2.1

d)      28.9 – 20.8 + 3.9

e)      108 ÷ 12 + 46 – 14

f)       1.8 x 2.4 – 2 x 2.1 + 0.12

g)      7 + 7 x 7 ÷ 7 – 7 + 7

h)      16 + 9 – 3 x 12 ÷ 6 – 5

i)        5.3 + 1.5 ÷ 5 x 2 

j)     3 + 3 x 4 ÷ 2

STD-6, CHAPTER-8: STRUCTURE AND FUNCTION OF LIVING ORGANISMS-PLANTS, EXERCISE QAs

 A.     FILL IN THE BLANKS.

1.      Maize, wheat and rice are examples of _____ roots.

Ans: fibrous

2.      Ginger and potato are two examples of modified ______.

Ans: stem

3.      The main function of the ______ is to prepare food for the plant.

Ans: leaf

4.      Banyan is an example of _____ roots.

Ans: prop

5.      ______ is the most attractive, and colourful, part of the plant.

Ans: flower

6.      The leaves of cacti are modified into ______.

Ans: spines

7.      The leaf blade is also known as ______.

Ans: lamina

B.      WRITE TRUE OR FALSE FOR THE FOLLOWING STATEMENTS.

 

1.      All plants possess the tap root system.                                                                     False

2.      The wheat and maize plants have a fibrous root system.                                     True

3.      Cactus plants photosynthesise through their stems.                                             True

4.      Leaves manufacture food for themselves.                                                               False

5.      Flower is meant for the reproduction of the plant.                                               True

6.      The pistil is the female part of a flower.                                                                   True

7.      Stigma and ovary have no role in reproduction of plants.                                    False

8.      Seeds store food for the future plant.                                                                       True

C.      TICK THE CORRECT OPTION.

 

1.      The roots, that are consumed as food, are-

(a)   Onion and sweet potato

(b)   Carrot and onion

(c)    Beet and turnip

(d)   Potato and radish      

      Ans: beet and turnip

2.      The plants manufacture food through the process of-

(a)   Transpiration

(b)   Water conduction

(c)    Photosynthesis

(d)   respiration           

      Ans: photosynthesis

3.      Leaves are attached to the stem at the-  

(a)   Nodes

(b)   Pedicel

(c)    Internode

(d)   stalk      

       Ans: nodes

4.      The total number of whorls, in a flower, is/are–

(a)   One

(b)   Two

(c)    Three

(d)   four                                   

      Ans: four

5.      The reproductive organ, of a plant, is the-

(a)   Flower

(b)   leaf

(c)    seed

(d)   root

      Ans: flower

6.      The part of the flower, that provides protection to the bud, before it blooms-

(a)   sepal

(b)   petals

(c)    stamen

(d)   pistil

      Ans: sepal

D.     ANSWER THE FOLLOWING QUESTIONS IN BRIEF.

 

1.      Name the two main systems of a plant.

Ans: The main systems of a plant are, The Root System and The Shoot System.

2.      Name the different parts of the shoot system.

Ans: The different parts of the shoot system are, stem, branches, flowers, fruits, leaves etc.

3.      Name different types of modified stems.

Ans: Different types of modified stems are,

i) Potato, ginger (food storage stems)

ii) Grapes and Pea tendrils (supporting stems)

iii) Cactus (food preparing stems)

4.      State the role of spines – the modified leaves.

Ans: i) The spines protect the plant from grazing animals.

ii) They also reduce the loss of water during excessively hot climates.

5.      Name the different parts of a flower.

Ans: The different parts of a flower are, pedicel, sepals, petals, stamen and pistil/carpel.

6.      Give the meaning of the term ‘pollination’.

Ans: The process of transfer of pollen grains from the anther to the stigma is called as pollination.

E.      ANSWER THE FOLLOWING QUESTIONS.

 

1.      State the differences between the two main systems of a plant.

Ans: i) The main systems of a plant are, The Root System and The Shoot System.

ii) The root system grows below the ground. But, the shoot system lies above the soil.

2.      Define root system. Give two functions of roots.

Ans: The Root System is that part of the plant which grows below the ground.

Functions of roots:

i) Root fixes the plant to the soil.

ii) Roots absorb water and minerals from the soil

3.      Define shoot system. Give two functions of the stem.

Ans: The part of the plant, which is found above the soil, is known as its shoot system.

Functions of the stem:

i) It keeps the plant straight and upright.

ii) It transports water and minerals, absorbed by the roots, to all parts of the plant.

4.      How is a tap root different from a fibrous root? Give one example of each type.

Ans: i) In tap root system, there is one main root and smaller lateral roots grows out of the main root. Example, Carrot.

ii) In fibrous root system, there is no main root. Several roots grow out from the base of the stem which are almost similar in size. Example, Rice.

5.      What is a leaf? Draw a diagram showing different parts of a leaf.

Ans: The leaf is the green coloured, thin, broad and flat part of a plant.

                           


6.      Name any two types of stem modifications, giving one example for each type.

Ans: i) Stem modified for storing food: Example, In Potato the stem lies underground and it stores food.

ii) Stem modified for manufacturing food: Example, in Cactus the stem is green in colour and prepares food.

7.      Name the two parts of a stamen. State the functions of each of these two parts,

Ans: The two parts of a stamen are: Anther and Filament.

i) The filament provides support to the anther.

ii) The anther produces pollen grains.

8.      What are the functions of a fruit?

Ans: The functions of a fruit are as follows:

i) It protects the seed against injury and other unfavourable climatic conditions.

ii) It helps in the dispersal of seeds.

iii) It stores food material, as in the case of tomato, apple and mango.

iv) Fruits are the edible part of a plant.

Tuesday 23 November 2021

STD-IX, GRAVITATION MCQs

 Two objects of different masses falling freely near the surface of the moon would

(a) have same velocities at any instant
(b) have different acceleration
(c) experience forces of same magnitude
(d) undergo a change in their inertia

The value of acceleration due to gravity
(a) is same on equator and poles
(b) is least on poles
(c) is least on equator
(d) increases from pole to equator

The gravitational force between two objects is F. If masses of both objects are halved without changing the distance between them, then the gravitational force would become
(a) F/4
(b) F/2
(c) F
(d) 2F

A boy is whirling a stone tied to a string in a horizontal circular path. If the string breaks, the stone
(a) will continue to move in the circular path
(b) will move along a straight line towards the centreof the circular path
(c) will move along a straight line tangential to the circular path
(d) will move along a straight line perpendicular to the circular path away from the boy

An object is put one by one in three liquids having different densities. The object floats with 19211 and 37 parts of their volumes outside the liquid surface in liquids of densities d1, d2 and d3respectively. Which of the following statement is correct?
(a) d1 > d2 > d3
(b) d1 > d2 < d3
(c) d1 < d2 > d3
(d) d1 < d2 < d3

In the relation F = GM mld2, the quantity G
(a) depends on the value ofg at the place of observation
(b) is used only when the Earth is one of the two masses
(c) is greatest at the surface of the Earth
(d) is universal constant of nature

Law of gravitation gives the gravitational force between
(a) the Earth and a point mass only
(b) the Earth and Sun only
(c) any two bodies having some mass
(d) two charged bodies only

The value of quantity G in the law of gravitation
(a) depends on mass of Earth only
(b) depends on radius of Earth only
(c) depends on both mass and radius of Earth
(d) is independent of mass and radius of the Earth

Two particles are placed at some distance. If the mass of each of the two particles is doubled, keeping the distance between them unchanged, the value of gravitational force between them will be
(a) 14 times
(b) 4 times
(c) 12 times
(d) unchanged

The atmosphere is held to the Earth by
(a) gravity
(b) wind
(c) clouds
(d) Earth’s magnetic field

The force of attraction between two unit point masses separated by a unit distance is called
(a) gravitational potential
(b) acceleration due to gravity
(c) gravitational field
(d) universal gravitational constant

The weight of an object at the centre of the Earth of radius R is (NCERT Exemplar)
(a) zero
(b) infinite
(c) R times the weight at the surface of the Earth
(d) 1/R2 times the weight at surface of the Earth

An object weighs 10 N in air. When immersed fully in water, it weighs only 8 N. The weight of the liquid displaced by the object will be
(a) 2 N
(b) 8 N
(c) 10 N
(d) 12 N

A girl stands on a box having 60 cm length, 40 cm breadth and 20 cm width in three ways. In which of the following cases, pressure exerted by the box will be
(a) maximum when length and breadth form the base
(b) maximum when breadth and width form the base
(c) maximum when width and length form the base
(d) the same in all the above three cases

An apple falls from a tree because of gravitational attractionbetween the Earth and the apple. If F1 is the magnitude of force exerted by the Earth on the apple and F2 is the magnitude of force exerted by the apple on the Earth, then
(a) F1 is very much greater than F2
(b) F2 is very much greater than F1
(c) F1 is only a little greater than F2
(d) F1 and F1 are equal

The acceleration due to gravity on the Earth depends upon the
(a) mass of the body
(b) mass of the Earth
(c) shape and size of the body
(d) volume of the body

When a mango falls from a mango tree then
(a) only the Earth attracts the mango.
(b) only the mango attracts the Earth.
(c) both the mango and the Earth attract each other.
(d) both the mango and the Earth repel each other.

When a ship floats in sea water
(a) The weight of water displaced is greater than the weight of ship
(b) The weight of water displaced is less than the weight of the ship
(c) The weight of water displaced is equal to the weight of the ship
(d) It displaces no water.

The SI unit of pressure is
(a) Nm2
(b) N/m
(c) N/m2
(d) N2/m2

If the gravitational attraction of the Earth suddenly disappears, which of the following statements will be true?
(a) The weight of body will become zero but the mass will remain same.
(b) The weight of a body will remain same but the mass will become zero.
(c) Both mass and weight become zero.
(d) Neither mass nor weight becomes zero.