An astronaut orbiting the earth in a circular orbit 120 km above the surface of earth, gently drops a spoon out of the space ship. The spoon will
fall vertically down to the earth
move towards the moon
will move along with the space ship
will move in an irregular way and then fall down to earth
When spoon is dropped gently, its tangential speed is equal to the speed of spaceship, and so it revolves like a satellite.
Which of the statements given below is/are correct? Permanent hardness of water is due to the presence of soluble.
1. chloride of calcium
2. bicarbonate of calcium
3. sulphate of magnesium
4. bicarbonate of magnesium
Select the correct answer using the codes given below.
1 and 3
2 and 4
1,2 and 3
Chlorides and sulphates of calcium and magnesium are responsible for permanent hardness of water.
Note: Bicarbonates are responsible for temporary hardness of water.
Why ethylene dibromide is added to petrol -
1. It increases the octane number of fuel
2. It helps in elimination of lead oxide
3. It removes the sulphur compound in petrol
4. It serves as a substitute of tetraethyl lead
1 and 2
2 and 3
Lead oxide deposit is harmful to engine life. Thus a small amount of ethylene dibromide is added to petrol for simultaneous removal of lead oxide.
Refrigeration helps in food preservation by
killing the germs
reducting the rate of biochemical reactions
destroying enzyme action
scaling the food with a layer of ice
Refrigeration helps in food preservation by reducing. The rate of biochemical reactions.
Earthquake (shock) waves are
An Earthquake is the result of a sudden release of energy in the Earth’s crust that creates seismic waves.
Fat can be separated from milk in a cream separation because of
Centrifugal force separates fat from milk.
Raw mangoes shrivel when pickled in brine. The phenomenon is associated with
increase of surface tension of fluid
decrease of surface tension of fluid
Raw mangoes shrivel when pickled in brine due to osmosis i.e. How of water from higher concentration to lower concentration through a semi-permeable membrane.
Half portion of a rectangular piece of ice is wrapped with a white piece of cloth w hile the other half with a black one. In this context, which one among the follow ing statements is correct?
Ice melts more easily under black wrap
Ice melts more easily under white w rap
No ice melts at all under the black wrap
No ice melts at all under the white wrap
Ice under black wrap will melt easily because dark colour (black) absorbs the most of light energy falling on it.
Mr X was advised by an arehitect to make outer walls of his house with hollow' bricks. The correct reason is that such walls
make the building stronger
help keeping inside cooler in summer and warmer in winter
prevent seepage of moisture from outside
protect the building from lightning
The hollow bricks provide thermal insulations; the air in hollow' bricks, does not allow' outside heat or cold in the house to go out or come in the house. So, it keeps house cool in summer and warm in winter.
If a ship moves from freshwater into seawater, it will
sink a little bit
rise a little higher
When a body is immersed in a fluid, the fluid exerts an upward force on it, called buoyant force.
and buoyant force x density of fluid.
As the density of sea water is higher than that of the fresh water.
So extra buoyant force and ship will rise a little higher.
The cat can survive fall from a height much more than human or any other animal. It is because the cat
can immediately adjust itself to land on all four paws and bend the legs to absorb the impact of falling
has clastic bones
has thick and elastic skin
also gets injury equally with other animals, but has tremendous endurance, resistance and speedy recovery
As the cat falls from a height, it bends the legs to absorb the impact of falling and immediately adjust itself.
Fire fly gives us cold light by virtue of the phenomenon of fluorescence
Fire fly gives us cold light due to chemiluminescence i.e. light produced by chemical reaction.
The best colours for a sun umbrella will be
black on top and red on inside
black on top and white on inside
red on top and black on inside
white on top and black on inside
As white colour reflects all the components of white light and black colour absorbs all the components of white light. So, the best colours for a sun umbrella, white on top and black on inside.
When ice melts, its
volume and mass both decrease
volume decreases while mass increases
When ice melts its density increases i.e. its volume decreases. Mass is a invariant quantity.
When deep sea fishes are brought to the surface of the sea, their bodies burst. This is because the blood in their bodies flows at very
When deep sea fishes are brought to the surface of the sea, their bodies burst, this is because the blood in their bodies flows at very high speed.
By what mechanism does scent spread all over the room if the lid is opened?
Pressure in the bottle
Compression from the bottle
Diffusion refers to the process by which molecules intermingle as a result of their kinetic energy of random motion.
When an incandescent electric bulb glows
the electric energy is completely converted into light
the electric energy is partly converted into light energy and partly into heat energy
the light energy is converted into electric energy
the electric energy is converted into magnetic energy
When current flows through the filament of incandescent electric bulb, it gets heated up. Soon it becomes white hot and starts emitting light.
In cricket match, while catching a fast moving ball, a fielder in the ground gradually pulls his hands backwards with the moving ball to reduce the velocity to zero. The act represents |
Newton’s first law of motion
Newton’s second law of motion
Newton’s third law of motion
Law of conservation of energy
We know from Newton’s second law of motion
Fexl = — when di is more Fcxt will be less.
The greater the rate of change of momentum, the greater is the force and vice-versa.
Two layers of a cloth of equal thickness provide warmer covering than a single layre of cloth with double the thickness. Why?
Because of the air encapsulated between two layers
Since effective thickness of two layers is more
Fabric of the cloth plays the role
Weaving of the cloth plays the role
Two layers of a cloth are wanner because air trapped between the layers acts as thermal insulator restricting the heat transfer.
What is the purpose of adding baking soda to dough? To generate moisture
To generate moisture
To give a good flavor
To give good color
To generate carbon dioxide
Baking soda has sodium bicarbonate as the chief constituent. It decomposes on heating giving carbon dioxide. This causes dough, cakes, biscuits etc. to expand and become light.
Match List I with List II and select the correct answer using the codes given below the Lists. List I List II Industries in which largely (Mineral) ' used) A. Limestone 1 Cement B. Copper 2 Electrical goods C. Bauxite 3 Manufacture of aeroplanes D. Manganese 4 Steel Codes A B C D
A : 1 B : 2 C : 3 D : 4
A : 4 B : 2 C : 3 D : 1
A : 1 B : 3 C : 2 D : 4
A : 4 B : 3 C : 2 D : 1
Solder Lead and tin
Brass Copper and zinc
Bronze Copper and tin
Steel Iron and carbon
Which one of the following is not needed in a nuclear fission reactor?
Substances like graphite and heavy water are used as moderator to slow dow n the speed of neutrons. Cd or B are used as control rods to control rate of fission by absorbing neutrons.
When items or jewellery made of metals such as copper or nickel are placed in a solution having a salt of gold, a thin film of gold is deposited by
cooling to below 0°C
heating above 100°C
passing an electric current
just keeping it for 10 min
The process of depositing a thin layer of one metal over the surface of other metal by the process of electrolysis is known as electroplating. Hence, when items or jewellery made of metals such as copper or nickel are placed in a solution having a salt of gold, a thin film of gold is deposited by passing an electric current.
Which one among the following is a sin smelling agent added to LPG cylinder to help the detection of gas leakage?
Ethyl mercaptan or thioethanol (C2H5SH) is added during filling of LPG cylinders. Il is a strong smelling compound and help in the detection of gas leakage.
A close bottle containing water at room temperature was taken to the Moon and then the lid is opened. The water will
decompose into oxygen and hydrogen
not change at all
The water will freeze because on Moon the temperature is below the freezing point i.e., very low.