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- Question 1 of 34
The period of revolution of a geostationary satellite is:
A geostationary satellite is an earth-orbiting satellite, placed at an altitude of approximately 35,800 km directly over the equator, that revolves in the same direction the earth rotates (west to east). At this altitude, one orbit takes 24 hours, the same length of time as the earth requires to rotate once on its axis. So they seem stationary, relative to the Earth’s surface.
- Question 2 of 34
A piece of paper and a cricket ball are dropped from the same height. Under which of the following conditions do both reach the surface simultaneously?
All objects, regardless of mass, will fall at the same rate. Heavier things have a greater gravitational force AND heavier things have a lower acceleration. It turns out that these two effects exactly cancel to make falling objects have the same acceleration regardless of mass.
- Question 3 of 34
A rocket works on the principle of conservation of:
A rocket works on the principle of conservation of linear momentum. Rocket ejaculates gases in backward direction which creates momentum of the gases backward and thus by conservation of momentum, the rocket gets momentum in the forward direction making it move forward.
- Question 4 of 34
The frequency of ultrasound waves is typically:
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Humans can detect sounds in a frequency range from about 20 Hz to 20 kHz. The frequency of ultrasound waves is above 20 kHz.
- Question 5 of 34
Optical fibres are based on the phenomenon of:
Optical fibre works on the principle of total internal reflection. When light ray strikes at the internal surface of an optical fibre cable called such that incidence angle is greater than critical angle, then incident light ray reflects in the same medium and this phenomenon repeats.
- Question 6 of 34
‘Mirage’ is an example of:
A mirage occurs because of total internal reflection by layers of air. When the ground is very hot and the air is cool. The hot ground warms a layer of air just above the ground. When the light moves through the cold air and into the layer of hot air it is refracted (bent). A layer of very warm air near the ground refracts the light from the sky nearly into a U-shaped bend.
- Question 7 of 34
The phenomenon of light associated with the appearance of the blue colour of the sky is:
The sky appears blue to the human eye as the short waves of blue light are scattered more than the other colours in the spectrum, making the blue light more visible.
- Question 8 of 34
The time period of a pendulum when taken to the Moon would:
When the pendulum is taken to the moon, the value of ‘g’ will decrease and hence time period will increase.
- Question 9 of 34
The atmospheric air is held to the Earth by:
The atmospheric air is held to the Earth by gravity. Our atmosphere is a mixture of gases that surround Earth. It is kept in place by the pull of Earth’s gravity.
- Question 10 of 34
The function of ball bearings in a wheel is to convert kinetic friction (sliding friction) into rolling friction.
The function of ball bearings in a wheel is:
- Question 11 of 34
‘Shock-absorbers’ are usually made of steel as it:
Shock-absorbers are usually made of steel as it has higher elasticity. They are used in vehicles so that the time interval of the jerk increases. Hence, the rate of momentum decreases. Therefore, during the jerk, a lesser force is exerted on the passengers.
- Question 12 of 34
Which of the following could be used as fuel in propellants or rockets?
Rocket engines and boosters carry both fuel and an oxidizer. For solid fuel, the components are aluminum and ammonium perchlorate. For liquid fuel, the components are liquid hydrogen and liquid oxygen. When combined, the fuels release water, which allows the rocket to leave the ground.
- Question 13 of 34
Lambert’s law is related to:
Lambert’s law is related to Illumination. It states that when light fall obliquely on a surface, the illumination of the surface is directly proportional to the cosine of the angle theta between the direction of incident light and surface normal.
- Question 14 of 34
One can distinguish a telescope from a microscope by observing:
Telescope and microscope can be distinguished by observing the length and size of the lens. In a telescope, the object lens has a large focal length and large aperture and the eye lens has small focal length and small aperture. The distance between the object lens and eye lens is adjusted to focus on the object situated at infinity. In a microscope, the object lens has a small focal length and short aperture and the eye lens used has a moderate focal length and large aperture. The object and eye lens are kept at a fixed distance apart, whereas the distance of the objective lens from the object is adjusted to focus an object.
- Question 15 of 34
The sound produced by a bat is:
Bats produce echolocation by emitting ultrasound waves through their mouth or nose and listening to the echo. With this echo, the bat can determine the size, shape and texture of objects in its environment.
- Question 16 of 34
When a bar magnet is cut into two equal halves (perpendicular to its length), the pole strength of each piece:
When a bar magnet is cut perpendicular to its length then the pole strength of each piece remains the same (but the magnetic moment is halved). If a magnet is cut parallel to its length then the pole strength of the pieces becomes half.
- Question 17 of 34
An electrostatic precipitator is used to control:
Electrostatic precipitators are used for air pollution control, particularly for removing harmful particulate matter from waste gases at industrial facilities and power-generating stations.
- Question 18 of 34
The time period of a seconds pendulum is:
A seconds pendulum is a pendulum whose period is precisely two seconds; one second for a swing in one direction and one second for the return swing, a frequency of 0.5 Hz.
- Question 19 of 34
Lakes freeze in cold countries in winter, leaving the water underneath at:
The density of water is maximum at 4°C. Water colder than 4°C floats to the top and warmer than 4°C sinks to the bottom. Eventually, the coldest water, which has floated to the top of the lake, freezes to form a layer of ice.
- Question 20 of 34
Which one of the following determines the sharpness of the image in a camera?
Aperture refers to the opening of a lens’s diaphragm through which light passes. It controls the brightness of the image that passes through the lens and falls on the image sensor. The camera sensor size is one of the key elements that affect the sharpness of an image.
- Question 21 of 34
For a person having hypermetropia, the near point is:
Hypermetropia, also known as long-sightedness, is a defect of vision in which a person can’t see the nearby object clearly (appears blurred), though can see the distant objects clearly. The near point of a hypermetropic eye is greater than 25 cm.
- Question 22 of 34
Amount of water vapour in the atmosphere is measured in terms of:
Humidity is a measure of the amount of water vapor in the air. Relative humidity measures the amount of water in the air in relation to the maximum amount of water vapor (moisture). The higher the temperature, the more water vapor the air can hold.
- Question 23 of 34
Name the process of production of energy in the Sun:
Solar energy is created by nuclear fusion that takes place in the sun. Fusion occurs when protons of hydrogen atoms violently collide in the sun’s core and fuse to create a helium atom. This process, known as a PP (proton-proton) chain reaction, emits an enormous amount of energy.
- Question 24 of 34
A spherical ball made of steel when dropped in a mercury container will:
A spherical ball made of steel when dropped in a mercury container will be on the surface of mercury because the density of mercury is higher than that of steel.
- Question 25 of 34
The sounds having a frequency of 20Hz to 20kHz are known as:
The sounds having a frequency range of 20Hz to 20kHz are known as audible sounds. All the frequencies residing between the limit of 20Hz and 20KHz can be perceived by human beings.
- Question 26 of 34
Eclipses occur due to which optical phenomena?
Rectilinear propagation describes the tendency of electromagnetic waves (sunlight) to travel in a straight line. Eclipses occur due to the rectilinear propagation of light. Whenever an obstacle is placed in the path of light, the shadow of the obstacle is seen on the other side.
- Question 27 of 34
Pure water is a bad conductor of electricity because it is:
Pure water is a bad conductor of electricity because it is feebly ionized. The presence of ions is necessary in order for any solution to conduct electricity. Pure water is free from any kind of acids, bases or salts. Hence, it does not conduct electricity due to the absence of ions.
- Question 28 of 34
Gamma rays have the greatest similarity with:
X-rays are similar to gamma rays in that they are photons of pure energy. X-rays and gamma rays have the same basic properties but come from different parts of the atom. X-rays are emitted from processes outside the nucleus, but gamma rays originate inside the nucleus.
- Question 29 of 34
The filament of electric bulb is made up of:
Tungsten metal is used for making the filament of electric bulbs because it has a very high melting point. Due to its high melting point, the tungsten filament can be kept white-hot without melting away.
- Question 30 of 34
When a vibrating tuning fork is placed on a table, a loud sound is heard. This is due to:
When a vibrating tuning fork is placed on a table, a loud sound is heard due to forced vibrations. The tendency of one object to force another adjoining or interconnected object into vibration motion is referred to as forced vibration.
- Question 31 of 34
A piece of wood is held underwater. The upthrust on it will be:
When a piece of wood is held underwater, the upthrust on it will be less than the weight of the wood. Here, the wooden piece is under the water because the upthrust force acting on the wood under the water is less than the weight of the wooden piece.
- Question 32 of 34
In a photocell light energy is converted into:
In a photocell, light energy is converted into electrical energy. A photocell is a resistor that changes resistance depending on the amount of light incident on it. It is an electron tube with a photosensitive cathode that emits electrons when illuminated and an anode for collecting the emitted electrons.
- Question 33 of 34
Among the following materials sound travels fastest in:
Among the given materials sound travels fastest in steel. Sound travels fastest through solids. This is because molecules in a solid medium are much closer together than those in a liquid or gas, allowing sound waves to travel more quickly through it. Sound cannot travel in a vacuum as there is no medium.
- Question 34 of 34
Which phenomenon do bats or dolphins use to find prey, predators or obstacles?
Echolocation is a physiological process for locating distant or invisible objects (such as prey) by means of sound waves reflected back to the emitter (such as a bat) by the objects. Echolocation is used for orientation, obstacle avoidance, food procurement, and social interactions.