6th sci semi 2nd
term IMP Q&A
Q.1. Identify the types of
motion.
(a) Movement of the earth
around the sun : Circular motion, periodic
motion.
(b) Movement of a ceiling
fan : Circular motion, Oscillatory motion.
(c) A meteor falling from
the sky : Linear motion.
(d) A rocket launched from
the ground : Linear motion.
(e) A fish swimming in water
: Random motion.
(f) The plucked string of a
sitar : Oscillatory motion.
Q.2. Fill in the blanks.
(1) If a ball is released from the terrace of a building, it comes
down in non-uniform linear motion. On the other
hand, it reaches the ground in non-linear motion if it is thrown with force away from
the terrace in a direction parallel to the terrace.
(2) The motion of an aero plane on the runway before take-off is linear motion .
(3) The kite looking for its prey flies with circular motion in the sky.
(4) Children sitting in a rotating giant wheel have uniform circular motion, while those
sitting in a merry-go-round have a non-uniform circular motion.
(5) Force has to be applied to change the direction of a moving object.
(6) When an elephant drags a wooden log over the land, the forces
that are applied on the log are muscular
force , gravitational
force and frictional force.
(7) A ball was set rolling on a large table. If its motion is to be changed, a force will have to be
applied on it.
(8) The force of friction always acts against the motion.
(9) A bucketful of water is to be drawn from a well. work will be done when a force is applied to do this,
because there will be a displacement of water.
(10) If a ball is dropped on the sloping roof of a house, it acquires
motion and falls on the
ground. That is, transformation of potential energy into kinetic energy takes place.
(11) You might have seen some beautiful fireworks during Diwali. It
is an example of transformation of chemical energy into light energy.
(12) The solar cooker is an application of the heat energy of the sun,
while solar cells, solar lamps are applications of the light energy of the sun.
(13) One labor carried four pans of road metal through a distance
of 100 metres. If he carries two pans of road metal through a 200 metre
distance equal work will be done.
(14) The capacity that an object has for doing work is called energy .
(15) The propagation of sound does not occur through a vacuum .
(16) Noise
pollution is a social issue.
(17) The sound which is disagreeable to the ears is called noise.
(18) Noise has adverse effects on our health .
(19) A star is a natural source of light.
(20) A candle is an artificial source of light.
(21) When light passes through a prism, it gets separated into seven colours.
(22) The image obtained in the pinhole camera is inverted .
(23) A shadow is formed when an opaque object comes in the way of light.
(24) When a transparent object comes in the way of light, light passes through it.
(25) If a bar magnet is hung by a thread tied at its centre, its
north pole becomes steady in the direction of the north Pole of the earth.
(26) If a bar magnet is cut into equal pieces by cutting it at right
angles to its axis at two places, 3 bar magnets are formed, and a total of 6 poles are formed.
(27) There is repulsion between the like poles of a magnet, and
attraction between its opposite poles.
(28) When magnetic material is taken close to a magnet, the material
acquires induced magnetism .
(29) If a magnet attracts a piece of metal, that piece must be made
of magnetic material or iron .
(30) A magnet remains steady in a north-south direction.
(31) The group of galaxies of which our Milky Way is a part is called
local group of galaxies .
(32) Comets are made of frozen
matter and dust particles .
(33) The planet Uranus appears as if it is rolling along its orbit.
(34) Jupiter is a stormy planet.
(35) The Pole Star is the best example of a variable type of star.
Group ‘A’ Group ‘B’
(1) An ox pulling a cart (a) Magnetic force
(2) Lifting a heavy iron object with a crane (b) Electrostatic force
(3) Weighing with a spring balance (c) Muscular force
(4) Applying brakes to a bicycle force (d) Gravitational
(5) Picking up pieces of paper with a plastic scale (e) Frictional force
(6) Rolling object (f) Heat energy
(7) Food (g) Atomic energy
(8) Stretched bow (h) Kinetic energy
(9) Sunlight (i) Potential energy
(10) Uranium (j) Chemical energy
(11) Mirror (k) non-luminous
(12) Firefly (l) Inverted image
(13) Pinhole camera (m) Reflection
(14) Moon (n) Luminous
(15) Galaxy (o) From east to west
(16) Comet (p) 33 satellites
(17) Sun-like star (q) Spiral
(18) Saturn (r) Sirius
(19) Venus (s) Halley
Answers:
(1) An ox pulling a cart - Muscular force
(2) Lifting a heavy iron object with a crane - Magnetic force
(3) Weighing with a spring balance - Gravitational
(4) Applying brakes to a bicycle - Frictional force
(5) Picking up pieces of paper with a plastic scale - Electrostatic force
(6) Rolling object - Kinetic
energy
(7) Food - Chemical energy
(8) Stretched bow - Potential
energy
(9) Sunlight - Heat energy
(10) Uranium - Atomic energy
(11) Mirror - Reflection
(12) Firefly - Luminous
(13) Pinhole camera - Inverted
image
(14) Moon - non-luminous
(15) Galaxy - Spiral
(16) Comet - Halley
(17) Sun-like star - Sirius
(18) Saturn - 33 satellites
Q.4. Say if the statements
given below are right or wrong. Rewrite the statements after correcting them.
(a) Venus is the planet
closest to the sun.
Answer: Wrong (Mercury is the planet closest to the sun.)
(b) Mercury is called a
stormy planet.
Answer: Wrong (Jupiter is called a stormy planet.)
(c) Jupiter is the biggest
planet.
Answer: Right.
Q.5. Classify the following as
a lever, a pulley and an inclined plane :
A wedge, a needle, a
staircase, a slide, the wheel of a flagpole, nutcrackers, scissors, an opener,
an axe, a crane, a knife.
|
Lever |
Pulley |
Inclined
plane |
|
Nutcrackers, Scissors, An
opener
|
Wheel
of a flagpole,
|
A
wedge, A needle, a
staircase, a
slide, an
axe, a
knife.
|
Q.6. Who is the odd-one-out
?
(1) Diesel, crude oil,
natural gas, wind
Answer: Wind. (Others are non-renewable fossil fuels.)
(2) A running car, hauling a
log, a book kept on a table, picking up the school bag.
Answer: a book kept on a
table. (Others are showing displacement and thus
possess kinetic energy.)
(3) Sunlight, wind, waves,
petrol
Answer: Petrol. (Others are renewable energy resources.)
(4) Leaving the fan on in a
vacant room, leaving the TV on while working, using AC during winter, putting
off the light when going out.
Answer: putting off the
light when going out. (This is the only way to
save energy, others are actions of wasting energy.)
Q.7. Giving one example
each.
(a) Linear motion : Parading soldiers, children playing on slide, Plane running on
runway, rocket launched from earth.
(b) Oscillatory motion : Swinging pendulum of clock, needle of sewing machine, vibrating
string of sitar.
(c) Circular motion : The giant wheel, fans, earth`s revolution, merry-go- round.
(d) Random motion : The swimming fish, flying butterfly, wandering animals.
(e) Periodic motion : Rotation of earth, rotation of hands of clock.
Q.8. Which machines will you
use to do the following work? Write their types.
|
Work |
Machine |
Type
of machine |
|
(a)To
remove the lid of a tin. |
Can
opener |
Inclined
plane(screw) |
|
(b)To
lift bricks to the top of a tall building. |
A
wheel and a rope to pick up the heavy load |
Pully |
|
(c)
To cut vegetables. |
Knife
or cutter |
Wedge |
|
(d)To
draw water from a well. |
A
pair of tongs |
Lever |
|
(e)
To hold a papad for roasting it. |
A plank |
Inclined
plane |
Q.9. Write whether of the
following objects are luminous or non-luminous.
|
Object
|
Luminous/non-luminous |
|
A
book |
non-luminous |
|
A
burning candle |
luminous |
|
A
wax cloth |
non-luminous |
|
A
pencil |
non-luminous |
|
A
pen |
non-luminous |
|
A
light bulb |
luminous |
|
A
tyre |
non-luminous |
|
A
torch |
luminous |
Q.10. Which magnet will you
use ?
(a) Iron is to be separated
from trash.
Answer: Electromagnet.
(b) You are lost in a
forest.
Answer: Mariner`s compass
(c) A window shutter opens
and shuts continuously in the wind.
Answer: Permanent magnet.
Q.11. Name these –
(a) Birth place of stars : Nebulae.
(b) Biggest planet in the solar
system : Jupiter.
(c) The galaxy which is our neighbour. : Andromeda(Devyani).
(d) Brightest planet in the
solar system : Venus.
(e) Planet with largest number of satellites : Jupiter.
(f) Planets without a single satellite : Mercury and Venus.
(g) Planet with a rotation
different from other planets. : Venus.
(h) A celestial body that
carries a tail along. : Comet.
Q.12. Answer the following
questions.
1) A bus covers a distance
of about two hundred kilometres from Solapur to Pune in five hours. How much
distance does the bus cover in one hour?
Ans. Formula:
Speed =Distance traversed / Time required for
traversing the distance
= 200 / 5
Therefore, Speed of the bus = 40 km/hr.
2) Why do you get hungry
after physical exercise?
Ans. Due to exercising, there is movement of
muscles and bones. The work done by the body muscles requires energy. This
energy is supplied by the heat energy produced by digestion of food. Food is
rich in chemical energy. This energy is converted into heat energy in our body.
When there is more demand for energy, we feel more hungry. Therefore, after
exercising we feel hungry.
3) In which form is energy
stored in plant food?
Ans. The energy is stored in the form of starch,
that is in the chemical form in the plant food.
4) When can an object be
seen?
Ans. The light rays from the source of the
light, fall on an object. When this light reflects from the surface of the
object, it enters our eyes. Therefore, we are able to see this object. The
luminous objects can be seen as they emit their own light.
5) What is a shadow ?
Ans. Shadow is produced by an opaque object.
Light does not pass through an opaque object. It does not reach the wall or any
other surface on the other side of the object. This part therefore remains
dark. This dark area is called the shadow of that object.
6) How is an electromagnet
made?
Ans. When an article of iron is wound by a
copper wire and the electric current is sent through the wire, the magnetism is
produced in this iron article. If the electric current is shut off, the
magnetism is lost. This is how temporarily magnetism can be produced by
creating electromagnetism.
7) What are
the types of galaxies ?
Ans. The types of galaxies are according to their shapes.
These are spiral, elliptical, barred spiral and irregular.
8) Name the different types
of stars.
Ans. There is a great variety in stars. Some are
very bright, some are faint. There are many colours among the stars, for example:
Blue, white, yellow and reddish. Some stars have varying brightness. Their
luminance changes constantly. According to these characters, the stars are of
the following subtypes: Sun-like Stars, Red Giants Stars, Super Nova, Binary or
Twin Stars and Variable Stars,
Q.13. Give reasons.
1) The ramp at a railway
station has a rough surface.
Ans. There should be more frictional force
created on the ramp of the railway station. If the surface is smooth and
slippery, there will be no frictional force. People using ramp in a hurry will
slip and fall down easily. In order to avoid this and keep people safe, the
ramp at a railway station has a rough surface.
2) An object thrown upwards
comes down after reaching a point.
Ans. An object thrown upwards goes up due to
muscular force. At one point during its ascent the muscular force becomes zero.
The gravitational force then starts operating on this object. It pulls this
object down. Thus, an object thrown upwards comes down after reaching a point.
3) Powder is sprinkled on a
carrom board.
Ans. The coins on the carrom board should move
swiftly during play. If powder is not sprinkled on the surface of the carrom
board, there would be more frictional force. This will hinder the play.
Therefore, to have a smooth carrom board surface, powder is sprinkled on a
carrom board.
4) Traveller's bags have
wheels.
Ans. Wheel is a simple machine. If the heavy bag
is to be lifted, it will require more effort. Instead, drawing it on wheels
become easier and efficient. It consumes lesser time and lesser energy to carry
a bag. Therefore, traveller's bags have wheels.
5) Machines have to be
maintained.
Ans. Parts of the machine undergo wear and tear.
Due to constant rubbing some parts may even get damaged. The weather, the rust
and the dust may spoil the parts of the machines. If the machine is not
functioning well, we may not use this facility when we need the most.
Therefore, machines need to be maintained regularly.
6) A bicycle is said to be a
complex machine.
Ans. A bicycle is made from combination of two
to three simple machines. The pedals, the handle, the wheels and the axle all
are simple machines. In combination they work together, therefore a bicycle is
said to be a complex machine.
