General Science – Physics MCQs
Q 1.Which of the following is responsible for the fact that Tennis ball bounces higher at high altitudes than in plains?
Answer: Correct Answer:C [ Less dense air ]
Notes: The rarified air at high altitudes gives less resistance to ball.
Notes: The rarified air at high altitudes gives less resistance to ball.
Q 2.Which among the following is true about latent heat ?
Answer: Correct Answer:C [It causes change in state or phase but not in temperature]
Notes: The latent heat Latent heat is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process. It causes change in state or phase but not in temperature.
Notes: The latent heat Latent heat is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process. It causes change in state or phase but not in temperature.
Q 3.On which of the following the jet Engine works?
Answer: Correct Answer:B [Conservation of Linear Momentum]
Notes: Conservation of Linear Momentum law says that if no external force acts on a system, then its total linear momentum remains conserved. In equation form, Momentum=mass*velocity. To increase the momentum of an object, we need to either increase its mass or velocity or both.Rockets work on law of conservation of momentum. As momentum in one direction is given to the rocket’s exhaust gases, momentum in the other direction is given to the rocket itself.
Notes: Conservation of Linear Momentum law says that if no external force acts on a system, then its total linear momentum remains conserved. In equation form, Momentum=mass*velocity. To increase the momentum of an object, we need to either increase its mass or velocity or both.Rockets work on law of conservation of momentum. As momentum in one direction is given to the rocket’s exhaust gases, momentum in the other direction is given to the rocket itself.
Q 4.A vehicle moving on a circular path experiences ________?
Answer: Correct Answer:A [centripetal force]
Notes: A vehicle moving on a circular path experiences centripetal force. Centripetal force that acts on a body moving in a circular path and is directed towards the centre around which the body is moving.
Notes: A vehicle moving on a circular path experiences centripetal force. Centripetal force that acts on a body moving in a circular path and is directed towards the centre around which the body is moving.
Q 5.If a moving body turns its speed to 1.5 times, what will be the impact on its kinetic energy?
Answer: Correct Answer:C [will become 2.25 times]
Notes: Kinetic Energy is a product of half the Mass times Velocity Squared. When the velocity is doubled, the Kinetic energy would go up four times. If velocity is tripled, kinetic energy would go up nine times. If velocity is increased by 1.5 times the Kinetic energy would go up by 1.5×1.5=2.25 times.
Notes: Kinetic Energy is a product of half the Mass times Velocity Squared. When the velocity is doubled, the Kinetic energy would go up four times. If velocity is tripled, kinetic energy would go up nine times. If velocity is increased by 1.5 times the Kinetic energy would go up by 1.5×1.5=2.25 times.
Q 6.What is the distance covered by a bus moving at a speed of 72 km/hr in a duration of 5 seconds?
Answer: Correct Answer:D [100 meters]
Notes: The solution involves converting the speed of the bus from km/hr to m/sec. This conversion is achieved by the formula speed (m/sec) = speed (km/hr) * 5/18. Thus, the speed becomes 20 m/s. The distance travelled by the bus in 5 seconds is the product of speed and time which gives us 100 meters. Therefore, option [D] or option 4 is the correct answer.
Notes: The solution involves converting the speed of the bus from km/hr to m/sec. This conversion is achieved by the formula speed (m/sec) = speed (km/hr) * 5/18. Thus, the speed becomes 20 m/s. The distance travelled by the bus in 5 seconds is the product of speed and time which gives us 100 meters. Therefore, option [D] or option 4 is the correct answer.
Q 7.If the distance between the earth and the sun becomes one-fourth of what it is now, the gravitational force exerted on the earth by the sun would be:
Answer: Correct Answer:C [ Sixteen times of what it is now]
Notes: Gravitational force is inversely proportional to the square of the distance between the bodies.
Notes: Gravitational force is inversely proportional to the square of the distance between the bodies.
Q 8.Which of the following waves is called compression-dilation waves or longitudinal waves?
Answer: Correct Answer:A [Primary waves]
Notes: Primary wave is also called compression-dilation or longitudinal waves. Secondary wave is called transversal wave. Love wave and Rayleigh wave are surface waves. P waves can pass through solid, liquid and gases and are also the fastest among the three main types of waves.
Notes: Primary wave is also called compression-dilation or longitudinal waves. Secondary wave is called transversal wave. Love wave and Rayleigh wave are surface waves. P waves can pass through solid, liquid and gases and are also the fastest among the three main types of waves.
Q 9.On heating a pure silicon circular disc with a circular hole at the centre, the diameter of the hole:
Answer: Correct Answer:B [ will contract]
Notes: Pure silicon has a negative coefficient of thermal expansion for temperatures and hence it shows contraction effect.
Notes: Pure silicon has a negative coefficient of thermal expansion for temperatures and hence it shows contraction effect.
Q 10.Which of the following is/are correct about Kinetic energy?
Answer: Correct Answer:D [None of the above]
Notes: Kinetic energy of a body is half the product of mass of the body and square of the velocity of the body. K.E = 1/2(mv2) Kinetic energy depends on the frame of reference. Kinetic energy of a body is always positive.
Notes: Kinetic energy of a body is half the product of mass of the body and square of the velocity of the body. K.E = 1/2(mv2) Kinetic energy depends on the frame of reference. Kinetic energy of a body is always positive.
Q 11.The energy by virtue of its position is known as:
Answer: Correct Answer:B [Potential energy]
Notes: The energy by virtue of its position is known as Potential energy. The energy by virtue of its motion is known as Kinetic energy.
Notes: The energy by virtue of its position is known as Potential energy. The energy by virtue of its motion is known as Kinetic energy.
Q 12.Which of the following has an effect on the value of acceleration due to gravity?
Answer: Correct Answer:D [All of the above]
Notes: The value of acceleration due to gravity vary due to the following factors : (a) Shape of the earth (b) Height above the earth surface (c) Depth below the earth surface (d) Axial rotation of the earth
Notes: The value of acceleration due to gravity vary due to the following factors : (a) Shape of the earth (b) Height above the earth surface (c) Depth below the earth surface (d) Axial rotation of the earth
Q 13.Water does not fall out of a glass when it is inverted inside a satellite, which is orbiting very close to the earth’s surface. Which of the following is the best reason for this?
Answer: Correct Answer:C [The water and the glass have the same acceleration due to gravity]
Notes: Water does not fall out of a glass when it is inverted inside a satellite, which is orbiting very close to the earth’s surface. The reason for this is that the water and the glass have the same acceleration due to gravity, equal to g, towards the centre of the earth. Hence there is no relative motion between them.
Notes: Water does not fall out of a glass when it is inverted inside a satellite, which is orbiting very close to the earth’s surface. The reason for this is that the water and the glass have the same acceleration due to gravity, equal to g, towards the centre of the earth. Hence there is no relative motion between them.
Q 14.The distance of Neptune and Saturn from sun are nearly 1013and 1012meters respectively. Assuming that they move in circular orbits, what will be the ratio of their periodic times?
Answer: Correct Answer:B [10√10]
Notes: By using Kepler’s third law, Tneptune/Tsaturn= (Rneptune/Rsaturn)3/2
Notes: By using Kepler’s third law, Tneptune/Tsaturn= (Rneptune/Rsaturn)3/2
Q 15.What will happen if a wire of length L is cut into two or more parts?
Answer: Correct Answer:B [each part can hold the same weight as full length wire]
Notes: If a wire of length L is cut into two or more parts, then it’s each part can hold the same weight. Since breaking force is independent of the length of wire.
Notes: If a wire of length L is cut into two or more parts, then it’s each part can hold the same weight. Since breaking force is independent of the length of wire.
Q 16.Which of the following is NOT an application of principle of floatation?
Answer: Correct Answer:D [None of the above]
Notes: The principle of floatation states that a floating object displaces its own weight of the fluid in which it floats. Some of the applications of the principle of Floatation:- 1. Ships 2. Balloons 3. Submarines
Notes: The principle of floatation states that a floating object displaces its own weight of the fluid in which it floats. Some of the applications of the principle of Floatation:- 1. Ships 2. Balloons 3. Submarines
Q 17.What will be the buoyant force acting on the stone, on being immersed in water, if it displaces 100gms of water?
Answer: Correct Answer:B [100 gm-weight]
Notes: As per Archimedes’ principle, if a stone, on being immersed in water, displaces 100gms of water, the buoyant force acting on the stone will be equal to 100gm-weight.
Notes: As per Archimedes’ principle, if a stone, on being immersed in water, displaces 100gms of water, the buoyant force acting on the stone will be equal to 100gm-weight.
Q 18.What do we call the potential energy of surface molecules per unit area of the surface?
Answer: Correct Answer:A [Surface energy]
Notes: The potential energy of surface molecules per unit area of the surface is called as surface energy. Some work is required to be done, in bringing a molecule from the interior of the liquid to the free surface, against the intermolecular force of attraction. This work which is stored as potential energy of the molecule on the surface.
Notes: The potential energy of surface molecules per unit area of the surface is called as surface energy. Some work is required to be done, in bringing a molecule from the interior of the liquid to the free surface, against the intermolecular force of attraction. This work which is stored as potential energy of the molecule on the surface.
Q 19.Which portion of the electromagnetic spectrum can be perceived by the human eye?
Answer: Correct Answer:A [Between 400 nm and 700 nm]
Notes: The human eye is capable of detecting light in the range of approximately 400 nm to 700 nm on the electromagnetic spectrum. This corresponds to the frequency range of about 4 × 10^14 to 7 × 10^14 Hz. This detection range falls within the visible light spectrum. It’s fascinating how our eyes are naturally tuned to this specific range, enabling us to perceive the palette of colors in our surroundings but unable to see ultraviolet or infrared radiation that are just outside this narrow band.
Notes: The human eye is capable of detecting light in the range of approximately 400 nm to 700 nm on the electromagnetic spectrum. This corresponds to the frequency range of about 4 × 10^14 to 7 × 10^14 Hz. This detection range falls within the visible light spectrum. It’s fascinating how our eyes are naturally tuned to this specific range, enabling us to perceive the palette of colors in our surroundings but unable to see ultraviolet or infrared radiation that are just outside this narrow band.
Q 20.What will be the apparent frequency when the both source of the sound and listener move in the same direction with same velocity?
Answer: Correct Answer:C [it will be equal to the actual frequency]
Notes: When both moves in the same direction with same velocity n’ = n, i.e. there will be no Doppler effect because relative motion between source and listener is zero.
Notes: When both moves in the same direction with same velocity n’ = n, i.e. there will be no Doppler effect because relative motion between source and listener is zero.
Q 21.What is a perfectly black body?
Answer: Correct Answer:A [A body which absorbs all the radiations incident on it]
Notes: A body which absorbs all the radiations incident on it is called a perfectly black body.
Notes: A body which absorbs all the radiations incident on it is called a perfectly black body.
Q 22.What is the absorptive power of a perfectly black body?
Answer: Correct Answer:B [1]
Notes: The absorptive power of a perfectly black body is maximum and its value is unity.
Notes: The absorptive power of a perfectly black body is maximum and its value is unity.
Q 23.What is meant by Calorimetry?
Answer: Correct Answer:A [Measurement of heat]
Notes: Calorimetry means measurement of heat. A device in which heat measurement can be done is called a calorimeter.
Notes: Calorimetry means measurement of heat. A device in which heat measurement can be done is called a calorimeter.
Q 24.Which of the following is the mirror formula?
Answer: Correct Answer:B [1/v + 1/u = 1/f]
Notes: Mirror formula represents image distance (v), object distance (u) and focal length (f) of the mirror. The mirror formula is 1/v + 1/u = 1/f. In case of lens it is 1/v – 1/u = 1/f.
Notes: Mirror formula represents image distance (v), object distance (u) and focal length (f) of the mirror. The mirror formula is 1/v + 1/u = 1/f. In case of lens it is 1/v – 1/u = 1/f.
Q 25.What is the size of the image formed by a concave mirror when the object is at focus?
Answer: Correct Answer:D [Highly enlarged]
Notes: Highly enlarged image is formed by a concave mirror when the object is at focus.
Notes: Highly enlarged image is formed by a concave mirror when the object is at focus.
Q 26.Which of the following cells is the basis of Non-rechargeable batteries?
Answer: Correct Answer:A [Galvanic cells]
Notes: Non-rechargeable batteries are examples of Galvanic cells.
Notes: Non-rechargeable batteries are examples of Galvanic cells.
Q 27.What do we call the cell that converts the potential energy from a fuel into electricity?
Answer: Correct Answer:D [Fuel cell]
Notes: A fuel cell is an electrochemical cell that converts the potential energy from a fuel into electricity through an electrochemical reaction of hydrogen fuel with oxygen or another oxidizing agent
Notes: A fuel cell is an electrochemical cell that converts the potential energy from a fuel into electricity through an electrochemical reaction of hydrogen fuel with oxygen or another oxidizing agent
Q 28.What is the process which causes the elimination of one or more electrons from the atomic shell known as?
Answer: Correct Answer:B [Ionisation]
Notes: Ionisation is any process which causes the addition of one or more extra electrons to the atomic shell or the elimination of one or more electrons from the atomic shell.
Notes: Ionisation is any process which causes the addition of one or more extra electrons to the atomic shell or the elimination of one or more electrons from the atomic shell.
Q 29.What is the SI unit of Force?
Answer: Correct Answer:C [Newton]
Notes: The Newton is the SI unit of force. It is the force that will give a mass of 1 kilogram an acceleration of 1 meter per second per second. The newton (symbol: N) is the International System of Units (SI) derived unit of force. It is named after Isaac Newton in recognition of his work.
Notes: The Newton is the SI unit of force. It is the force that will give a mass of 1 kilogram an acceleration of 1 meter per second per second. The newton (symbol: N) is the International System of Units (SI) derived unit of force. It is named after Isaac Newton in recognition of his work.
Q 30.What is the other name of Galileo’s law of falling bodies?
Answer: Correct Answer:B [Newton’s first law]
Notes: Newton’s first law of motion is referred to as the law of inertia. An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Notes: Newton’s first law of motion is referred to as the law of inertia. An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Q 31.Which of the following energy transformation takes place in microphone?
Answer: Correct Answer:B [Electrical into sound energy]
Notes: Microphone is a transducer that converts sound into an electrical energy. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recording, radio and television broadcasting.
Notes: Microphone is a transducer that converts sound into an electrical energy. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recording, radio and television broadcasting.
Q 32.Why do you feel chill after having a dip in sea water?
Answer: Correct Answer:B [Evaporation of water from the body]
Notes: The sea water first makes us feel cool because of its cool temperature, then after sometime it makes our body chill due to the process of evaporation. But sweat will only evaporate in an environment where there isn’t much water in the air. In a place with high humidity, there’re already lots of water molecules in the air.
Notes: The sea water first makes us feel cool because of its cool temperature, then after sometime it makes our body chill due to the process of evaporation. But sweat will only evaporate in an environment where there isn’t much water in the air. In a place with high humidity, there’re already lots of water molecules in the air.
Q 33.When a brick is dropped in water, bubbles are seen to rise. This is due to which of the following reasons?
Answer: Correct Answer:A [Air in the pores of the brick]
Notes: A brick is made when mud is heated and hence it remains porous. When brick is dropped in water the air which was trapped in those pores rise up and hence form the bubbles.
Notes: A brick is made when mud is heated and hence it remains porous. When brick is dropped in water the air which was trapped in those pores rise up and hence form the bubbles.
Q 34.How do the Ball-bearings reduce the friction?
Answer: Correct Answer:A [Reducing the area of contact with the use of metallic balls]
Notes: Bearings reduce the friction of certain moving parts by replacing sliding friction with rolling friction. They are used to provide better linear motion or rotation around a fixed axis. Roller bearings are typically cylinders similar to free rollers, while ball bearings are spheres that are held in a track.
Notes: Bearings reduce the friction of certain moving parts by replacing sliding friction with rolling friction. They are used to provide better linear motion or rotation around a fixed axis. Roller bearings are typically cylinders similar to free rollers, while ball bearings are spheres that are held in a track.
Q 35.Atmospheric pressure exerted on earth is due to the which of the following reasons?
Answer: Correct Answer:C [Gravitational pull]
Notes: The atmospheric pressure at the surface of the Earth is due to gravitational pull of the earth and is about 14.7 psi. That means that the weight of a column of air which has a cross section of 1 square inch and which stretches from the surface of the Earth to space is 14.7 pounds.
Notes: The atmospheric pressure at the surface of the Earth is due to gravitational pull of the earth and is about 14.7 psi. That means that the weight of a column of air which has a cross section of 1 square inch and which stretches from the surface of the Earth to space is 14.7 pounds.
Q 36.In which one among the following is the speed of sound maximum?
Answer: Correct Answer:D [Wood]
Notes: It depends on the temperature and material. Since sound is transferred easily through densely packed molecules, it is faster in denser substances. Thus the speed of sound increases with the stiffness of the material. So in wood the speed of sound is maximum.
Notes: It depends on the temperature and material. Since sound is transferred easily through densely packed molecules, it is faster in denser substances. Thus the speed of sound increases with the stiffness of the material. So in wood the speed of sound is maximum.
Q 37.What is the basic particle of light called?
Answer: Correct Answer:A [Photons]
Notes: The fundamental/basic particles of light are called as photons as conceived by Albert Einstein.
Notes: The fundamental/basic particles of light are called as photons as conceived by Albert Einstein.
Q 38.Which among the following quantities does not have units?
Answer: Correct Answer:B [Strain]
Notes: As the strain is defined as the ratio of elongation to the original length of the material due to stress applied on it, strain has no units and dimensions.
Notes: As the strain is defined as the ratio of elongation to the original length of the material due to stress applied on it, strain has no units and dimensions.
Q 39.Which of the following fundamental forces of nature is responsible for the conversion of a neutron into a proton, an electron and an anti-neutrino?
Answer: Correct Answer:B [Weak Nuclear force]
Notes: The gravitational force is a weak and is always attractive in nature. It acts between any two pieces of matter in the Universe since mass is its source.The weak force is responsible for radioactive decay and neutrino interactions. It causes Beta-decay ie. the conversion of a neutron into a proton, an electron and an antineutrino.The electromagnetic force causes electric and magnetic effects such as the repulsion between like electrical charges or the interaction of bar magnets. It can be attractive or repulsive and acts only between pieces of matter carrying an electrical charge. Electricity, magnetism, and light are all produced by this force.Strong Nuclear Force is responsible for holding the nuclei of atoms together. It is basically attractive but can be effectively repulsive in some circumstances. The strong force is ‘carried’ by particles called gluons; that is, when two particles interact through the strong force, they do so by exchanging gluons. Thus, the quarks inside of the protons and neutrons are bound together by the exchange of the strong nuclear force.
Notes: The gravitational force is a weak and is always attractive in nature. It acts between any two pieces of matter in the Universe since mass is its source.The weak force is responsible for radioactive decay and neutrino interactions. It causes Beta-decay ie. the conversion of a neutron into a proton, an electron and an antineutrino.The electromagnetic force causes electric and magnetic effects such as the repulsion between like electrical charges or the interaction of bar magnets. It can be attractive or repulsive and acts only between pieces of matter carrying an electrical charge. Electricity, magnetism, and light are all produced by this force.Strong Nuclear Force is responsible for holding the nuclei of atoms together. It is basically attractive but can be effectively repulsive in some circumstances. The strong force is ‘carried’ by particles called gluons; that is, when two particles interact through the strong force, they do so by exchanging gluons. Thus, the quarks inside of the protons and neutrons are bound together by the exchange of the strong nuclear force.
Q 40.When a body falls from an aeroplane, there is increase in its__:
Answer: Correct Answer:C [Acceleration]
Notes: The energy possessed by a body by virtue of its motion is called kinetic energy. Potential Energy is the energy possessed by virtue of its position or configuration. When a body falls from an aeroplane, there is increase in its acceleration as it fall under the influence of force of gravity.
Notes: The energy possessed by a body by virtue of its motion is called kinetic energy. Potential Energy is the energy possessed by virtue of its position or configuration. When a body falls from an aeroplane, there is increase in its acceleration as it fall under the influence of force of gravity.
Q 41.Which of the following is the unit of perceived loudness of sound ?
Answer: Correct Answer:B [Sone]
Notes: Perceived loudness of sound is a psycho-acoustic quantity that depends on sound pressure level, the frequency spectrum, and the time behavior of the sound. The sone is a unit of perceived loudness that was proposed by Stanley Smith Stevens in 1936.Being a unit of how loud a sound is perceived, the sone scale of loudness is based on data obtained from subjects who were asked to judge the loudness of pure tones and noise. One sone is arbitrarily set equal to the loudness of a 1,000-hertz tone at a sound level of 40 decibels.
Notes: Perceived loudness of sound is a psycho-acoustic quantity that depends on sound pressure level, the frequency spectrum, and the time behavior of the sound. The sone is a unit of perceived loudness that was proposed by Stanley Smith Stevens in 1936.Being a unit of how loud a sound is perceived, the sone scale of loudness is based on data obtained from subjects who were asked to judge the loudness of pure tones and noise. One sone is arbitrarily set equal to the loudness of a 1,000-hertz tone at a sound level of 40 decibels.
Q 42.In which form, the supplied heat energy is stored during change in temperature of substance?
Answer: Correct Answer:B [Kinetic energy]
Notes: Temperature is used as a measure for heat in an object by measuring the amount of kinetic energy in the molecules that make up the object. It is a measure of the average kinetic energy of the random molecular motion. Heat is a form of energy that can be transferred from the heat source to the molecules, and it can also change its form from heat to movement. The molecules that gain extra energy will have a higher frequency than the molecules that have not gained the extra energy.
Notes: Temperature is used as a measure for heat in an object by measuring the amount of kinetic energy in the molecules that make up the object. It is a measure of the average kinetic energy of the random molecular motion. Heat is a form of energy that can be transferred from the heat source to the molecules, and it can also change its form from heat to movement. The molecules that gain extra energy will have a higher frequency than the molecules that have not gained the extra energy.
Q 43.What is the minimum distance (in metres) required to hear an echo?
Answer: Correct Answer:C [17]
Notes: The human ear cannot distinguish echo from the original direct sound if the delay is less than 1/15 of a second. The velocity of sound in dry air is approximately 343 m/s at a temperature of 25°C. Therefore, the reflecting object must be more than 17.2m from the sound source for echo to be perceived by a person located at the source.
Notes: The human ear cannot distinguish echo from the original direct sound if the delay is less than 1/15 of a second. The velocity of sound in dry air is approximately 343 m/s at a temperature of 25°C. Therefore, the reflecting object must be more than 17.2m from the sound source for echo to be perceived by a person located at the source.
Q 44.Rainbow is formed due to which of the below phenomena?
Answer: Correct Answer:D [refraction and reflection]
Notes: A rainbow is an optical phenomenon that is caused by dispersion, refraction and reflection of light in water droplets resulting in a spectrum of light appearing in the sky. It is caused by light being refracted (bent), dispersed and then finally reflected from back surface to be seen by viewer. To watch rainbow the position of sun has viewer and water droplets in the front. In a rainbow, rains drops in the air cuts as a tiny prisms.
Notes: A rainbow is an optical phenomenon that is caused by dispersion, refraction and reflection of light in water droplets resulting in a spectrum of light appearing in the sky. It is caused by light being refracted (bent), dispersed and then finally reflected from back surface to be seen by viewer. To watch rainbow the position of sun has viewer and water droplets in the front. In a rainbow, rains drops in the air cuts as a tiny prisms.
Q 45.When we see an object, the image formed on the retina is__:
Answer: Correct Answer:A [Real and inverted]
Notes: The retina is the thin light-sensitive membrane lining the inner eyeball-towards the back of the eye. As our eye lens are convex in nature, they form mostly real, diminished i. e. reduced size and inverted images on the retina. When the images formed are real and inverted, the message sent by the optic nerve are chemical impulses which turn them into erect images that we see.
Notes: The retina is the thin light-sensitive membrane lining the inner eyeball-towards the back of the eye. As our eye lens are convex in nature, they form mostly real, diminished i. e. reduced size and inverted images on the retina. When the images formed are real and inverted, the message sent by the optic nerve are chemical impulses which turn them into erect images that we see.
Q 46.The coil wire in the electric room heater or electric cooking heater is called _____.
Answer: Correct Answer:B [Element]
Notes: This coil of wire in an electric room heater or electric cooking heater is called an element. When these appliances are switched on after connecting to the electric supply, their elements become red hot and give out heat. The amount of heat produced in a wire depends on its material, length and thickness.
Notes: This coil of wire in an electric room heater or electric cooking heater is called an element. When these appliances are switched on after connecting to the electric supply, their elements become red hot and give out heat. The amount of heat produced in a wire depends on its material, length and thickness.
Q 47.Kilowatt hour (kWh) represents the unit of which of the following?
Answer: Correct Answer:D [Energy]
Notes: The kilowatt hour is a composite unit of energy equivalent to one kilowatt (1 kW) of power sustained for one hour. One watt is equal to 1 J/s. One kilowatt hour is 3.6 megajoules. The kilowatt hour is commonly used as a billing unit for energy delivered to consumers by electric utilities.
Notes: The kilowatt hour is a composite unit of energy equivalent to one kilowatt (1 kW) of power sustained for one hour. One watt is equal to 1 J/s. One kilowatt hour is 3.6 megajoules. The kilowatt hour is commonly used as a billing unit for energy delivered to consumers by electric utilities.
Q 48.What is the direction of magnetic field lines in a magnet?
Answer: Correct Answer:C [North pole to South pole]
Notes: Magnetic field lines or lines of force are the imaginary lines introduced by Michael Faraday (1791- 1867) to visualize magnetic field. Lines of force are graphical representation of a field. The lines of force are the path along which an isolated unit North Pole would move along in the field. A magnetic field line is directed from North Pole to South Pole outside the magnet and from south pole to north pole inside the magnet.
Notes: Magnetic field lines or lines of force are the imaginary lines introduced by Michael Faraday (1791- 1867) to visualize magnetic field. Lines of force are graphical representation of a field. The lines of force are the path along which an isolated unit North Pole would move along in the field. A magnetic field line is directed from North Pole to South Pole outside the magnet and from south pole to north pole inside the magnet.
Q 49.Which electromagnetic radiation is used for satellite communication ?
Answer: Correct Answer:C [Microwave]
Notes: Microwave electromagnetic radiation is used for satellite communication. They propage undeviated from the sender to satellite and then back of the expected receiver.
Notes: Microwave electromagnetic radiation is used for satellite communication. They propage undeviated from the sender to satellite and then back of the expected receiver.
Q 50.Which one among the following is not an electromagnetic wave?
Answer: Correct Answer:C [Cathode Ray]
Notes: In physics, electromagnetic radiation (EMR) refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through space carrying electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma radiation only.
Notes: In physics, electromagnetic radiation (EMR) refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through space carrying electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma radiation only.
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