In a river, the currents are fastest where the river la
wide and shallow
narrow and shallow
wide and deep
narrow and deep
Correct Answer :
B. narrow and shallow
Related Questions
Formation of shadows can be explained by
rectilinear propagation of light
reflection
refraction
total internal reflection
The minimum velocity required by a satellite to escape earth's gravitational pull is
18 km/s
11.2 km /s
21 km/s
35 km/s
In a hydraulic pressure
force on each square centimetre of the small piston is less than the force on each square centimetre of the large piston
the distance the small piston moves is equal to the distance the large piston moves
applied pressure is equally transmitted throughout the liquid in all directions
force acting on small piston is equal to the force acting on large piston
The stars that shine brightly then dimly and then brightly are known as
meteors
binaries
variable stars
bright stars
Which of the following has the highest refractive index?
Crown glass
Water
Flint glass
Diamond
The scientist who first sent electromagnetic waves to distant places was
James Clerk Maxwell
Heinrich Hertz
Thomas Alva Edison
Baird
The atmosphere gets heated up mainly by
direct sun's rays
radiation from earth's surface
radiogenic heat (resulting from radioactive decay)
cosmic rays coming from space
A piece of cork la embedded inside an ice block which floats in water. What will happen to the level of water when all ice melts?
It will go down
It will come up
It will remain at the same level
First it will go down and it will come up
The force that keeps a body in a circular motion la called
the centripetal force
the centrifugal force
the frictional force
All the above
A hydrogen bomb is based on
nuclear fusion
nuclear fission
Both (a) and (b) above
Neither (a) nor (b)
In a microphone
sound energy is converted into electrical energy
electrical energy is converted into sound energy
sound energy is converted into mechanical energy
mechanical energy is converted into sound energy
The filament lamp is an example for
fluorescence
incandescence
both (a) and (b)
None of these
When an electric bulb breaks, there is an explosive sound. That is due to
the chemical reaction between the gases inside the bulb
the compressed gases inside rushing out suddenly
the air outside rushing in to fill the vacuum inside the bulb
None of the above
Which of the following has the highest refractive index?
Crown glass
Water
Flint glass
Diamond
If an empty cylinder Is half ruled with a liquid, Its centre of gravity is
shifted upwards
shifted downwards
shifted neither upward nor downward
shifted upward or downward depending on the density of the liquid
A transformer
converts direct current into alternating current
converts alternating current into direct current
steps up or steps down a given alternating current voltage
supplies current with zero resistance
The best estimates of the age of the earth comes from the studies of
angle of inclination of the earth
changes in radio-active minerals in it
period taken by Sun's light to reach the earth
artificial satellites revolving round the earth
Which of the following pairs is not correct?
Television - Baird
Transistor ~ Shockley
Thermometer - Celsius
Barometer Torricelli
Why is it cool near an open pond on a hot summer day?
Evaporation at the surface causes cooling
The heat obsorbed at the surface is passed on to the bottom
Because of impurity in the water
Because of convection currents set up inside water
In a freezer ice cubes will be formed more quickly in trays made of
rubber
plastic
aluminium
wood
When a ship floats on water, the weight or water displaced is
an indeterminate quantity
equal to the weight of the ship
greater than the weight of the ship
less than the weight of the ship
The force of attraction or repulsion between two charged bodies is directly proportional to the product of the charges and inversely proportional to the square of distance between them. This was propounded by
Coulomb
Gilbert
Volta
Rutherford
The extremely luminous objects located at the centre of some distant galaxies and which are sources of high energy electromagnetic radiation are known as
Nebulae
Quasars
Meteors
Comets
When a swing is drawn to a side Its potential energy In relation to the earth
increases
decreases
remains the same
is constant
Choose the correct answer
Microphone converts sound energy into electrical energy.
Electric fan converts electrical energy into mechanical energy.
Battery converts chemical energy into electrical energy.
All the above
Some persons are not able to see distant objects clearly because the image of the object is focused in front of the retina. This defect is known as
short sight
long sight
astigmatism
presbyopia
Alternating Current (AC) is more advantageous than direct current because
it can be transmitted easily and efficiently
Alternating Current (AC) loses the least amount of energy when transmitted at high voltages
Alternating Current (AC) voltage can be easily increased or decreased
all the above
The earth's nearest neighbour in space is
the Sun
the Moon
the Venus
the Mars
The ringing of an electric bell in an enclosed evacuated glass bell jar is not heard outside because
the ringing is not loud enough
the glass of the bell jar absorbs the sound waves
the bell jar is too small
there is no air or -any other gas in the bell jar
The pressure of air at high altitude is less than the atmospheric pressure at the sea level. Hence the boning point of water at a hill top
is more than at sea level
is equal to that sea level
is less than at sea level
depends on the surrounding temperature