1. Rate of doing work is called
a) Capacity
b) Energy
c) Power
d) current
Explanation: In physics, power is the rate of doing work. It is the amount of energy consumed per unit time. The unit of power is the joule per second (J/s), known as the watt.
2. The energy associated with motion is called
a) Potential energy
b) kinetic energy
c) Both A & B
d) None of the above
Explanation: The energy associated with motion is called kinetic energy.
3. The boiling point of water decreases at higher altitudes is due to
a) Low temperature
b) Low atmospheric pressure
c) High temprature
d) High atmospheric pressure
Explanation: The boiling point of water decreases at higher altitudes is due to low atmospheric pressure.
4. At boiling point of liquids, its
a) Temperature increases
b) Atmospheric pressure increases
c) Temperature remains constant
d) Vapour pressure decreases
Explanation: At boiling point of liquids, its temperature remains constant.
5.Contact force is another name for ________
a) Friction
b) Magnetic force
c) Electrostatic force
d) Muscular force
Explanation: Contact force is another name for Muscular force.
6. Fuse wire is made of an alloy of
a) Tin and Lead
b) Tin and Copper
c) Lead and Copper
d) Copper and Silver
Explanation: An electrical fuse is a safety device in the circuit that protects electrical systems by breaking the connection when a short circuit is occurring. The fuse wire is made up of Sn (tin) and Pb (lead) alloy because of its high resistance and low melting point.
7. In the electrical circuit of a house, the fuse acts as
a) A load
b) A thermopile
c) A safety device
d) A step down device
Explanation: In the electrical circuit of a house, the fuse acts as a safety device.
8. The nature of fuse wire is
a) High resistance and low melting point.
b) High resistance and high melting point.
c) Low resistance and high melting point.
d) Low resistance and low melting point.
Explanation: The nature of fuse wire is high resistance and low melting point.
9. Which of these is exhibiting kinetic energy?
a) An archer with a flexed bow
b) A person sitting on a couch while watching TV
c) A space station orbiting Earth
d) All of the above
Explanation: A space station orbiting Earth is exhibiting kinetic energy.
10. An object having the capability to do work is said to possess
a) Inertia
b) Force
c) Pressure
d) Energy
Explanation: An object having the capability to do work is said to possess Energy.
11. The fuse in an electric circuit is connected in
a) Series with neutral
b) Parallel to live
c) Parallel to neutral
d) Series with live
Explanation: Fuses are always connected in series with the components to be protected from overcurrent, so that when the fuse blows (opens) it will open the entire circuit and stop current through the components.
12. Working of safety fuses depends upon
1. magnetic effect of the current
2. chemical effect of the current
3. magnitude of the current
4. heating effect of the current
Select the correct answer using the code given below.
a) 1, 2, 3 and 4
b) 1, 2 and 3 only
c) 3 and 4 only
d) 4 only
Explanation: Working of safety fuses depends upon magnitude of the current and heating effect of the current.
13. During thunderstorm you are travelling in a car. To protect yourself from the lightning you will have to
a) Remain in the car
b) Get out of the car and lie flat in the ground
c) Abandon the car and take shelter under a nearby tree
d) Touch the nearest electric pole
Explanation: During thunderstorm you are travelling in a car. To protect yourself from the lightning you will have to remain in the car.
14. The unit of electrical power is
a) Bolt
b) watt
c) Kilowatt hour
d) Ampere
Explanation: The unit of electrical power is Watt.
15.Safety fuse wire used in domestic electrical appliances is made of metal of low
a) Resistance
b) Melting point
c) Specific gravity
d) Conductance
Explanation: For safety, the fuse wire used in the mains for household supply of electricity must be made of metal having low melting point.
16. It is easier to roll a barrel full of coal tar than to pull it because
a) the full weight of the barrel comes into play when it is pulled
b) the rolling friction is much less than the sliding friction
c) more surface area of the barrel is in contact with the road when it is pulled
d) coal tar is a liquid and it flows in the barrel when it is rolled
Explanation: When a body slides (moves with all its surface area in contact) over another body, the resistance faced is due to sliding friction. Hence rolling friction is less than the sliding friction. Thus it is easier to roll a barrel full of coal tar than to pull it.
17. Minimum number of unequal vectors which can give zero resultant are
a) two
b) three
c) four
d) more than four
Explanation: The minimum number of vectors of unequal magnitude required to produce zero resultant is three.
18. Intensity of sound has
a) an object existence
b) a subject existence
c) no existence
d) both subjective and objective existence
Explanation: Intensity of sound has an object existence
19. Rain is falling vertically downwards. To a man running east-wards, the rain will appear to be coming from
a) east
b) weast
c) northeast
d) southeast
Explanation: With vertical, the relative velocity will be inclined and appear to be coming from east.So the rain will appear to be coming from east.
20. An aeroplane is flying horizontally with a velocity of 600 km/h and at a height of 1960 m. When it is vertically at a point A on the ground a bomb is released from it. The bomb strikes the ground at point B. The distance AB is
a) 1200 m
b) 0.33 km
c) 3.33 km
d) 33 km
Explanation: 3.33 km
21. The rotational effect of a force on a body about an axis of rotation is described in terms of
a) Centre of gravity
b) Centripetal force
c) Centrifugal force
d) Moment of force
Explanation: The rotational effect of a force on a body about an axis of rotation is described in terms of moment of force.
22. At hill stations, the boiling point of water will be
a) Same as at sea level
b) Less than that at sea level
c) More than that at sea level
d) Equal to the melting point of ice
Explanation: The boiling point is the temperature at which the vapour pressure of the liquid equals the environmental pressure surrounding the liquid. Atmospheric pressure is due to air above any given point. The atmospheric pressure at high altitudes like hill station is less than at the sea level.Thus, vapour pressure will equal atmospheric pressure at a comparatively low temperature. Thus, the boiling point of water is reduced less than at sea level.
23. Instrument used to measure the force and velocity of the wind is
a) Ammeter
b) Anemometer
c) Altimeter
d) Audiometer
Explanation: An anemometer is a device used for measuring wind speed and direction. It is also a common weather station instrument.
24. When pressure is increased the melting point of ice
a) increase
b) Does not change
c) Decreases
d) Depends on the impurities in the ice
Explanation: The melting point of ice decreases when pressure increases because when pressure is increased volume is decreased and volume of water is less than ice.
25.The wall of a dam is made thicker at the bottom than at the top because the pressure exerted by the water on the wall
a) Depends on the thickness of the wall
b) Increases with height of the wall
c) Increases with depth of the wall
d) Depends on the area of the wall
Explanation: The pressure applied to walls of the dam will be a function of the amount of water that is over that particular point on the wall. So water pressure is very large at the bottom due to its large depth. That's why dams are constructed thicker at their bottoms than at their tops.
26. In which form is the supplied heat energy stored during change in temperature of substance?
a) Heat energy
b) Kinetic energy
c) Potential energy
d) Both kinetic and potential energy
Explanation: Kinetic energy is the supplied heat energy stored during change in temperature of substance.
27. What is another name for energy of motion ?
a) Motional energy
b) Potential energy
c) kinetic energy
d) Rotational energy
Explanation: Kinetic energy is the energy of motion.
28. The rate at which energy is transferred is called
a) power
b) watt
c) volt
d) Potential
Explanation: The rate at which energy is transferred is called power and the amount of energy that is usefully transferred is called efficiency.
29. An object with a mass of 22 kg moving with a velocity of 5 m/s possesses a kinetic energy of :
a) 275 J
b) 110 J
c) 2750 J
d) 110 J
Explanation: 275 J
30. In which of the following processes is energy released ?
a) Respiration
b) Photosynthesis
c) Ingestion
d) Absorption
Explanation: Energy is released during respiration.
31. Which tube used to produce X-ray?
a) Coolidge tube
b) X-ray tube
c) Roentgen
d) None of these
Explanation: Coolidge tube is used to produce X-ray
32. A Fuse wire is characterised by
a) High resistance and low melting point
b) High resistance and high melting point
c) Low resistance and high melting point
d) Low resistance and low melting point
Explanation: Fuse is a piece of wire of a material with a very low melting point. When a high current flows through the circuit due to overloading or a short circuit, the wires gets heated and melts. As a result,the circuit is broken and current stops flowing.
33. When the main switch of the house is put off it disconnects the
a) Live wire only
b) Live wire and the earth wire
c) Live wire and the neutral wire
d) Earth wire and the neutral wire
Explanation: It disconnects the live and neutral wire.
34. Electric power is measured in units of
a) Volt
b) Joule
c) watt
d) Ampere
Explanation: Electricity is measured in Watts and kilowatts.
35.Find the current (in A) when a charge of 500 Coulomb flows in 25 seconds.
a) 12500
b) 20
c) 40
d) 6250
Explanation: Current = Charge/Time
I = Q/t
I = 500/25
I = 20 A.
36. Energy per unit volume is dimensionally equal to
a) pressure
b) Force
c) Density
d) work
Explanation: Energy per unit volume is dimensionally equal to pressure.
37.To open a door easily, the handle should be fixed
a) Near the hinges
b) Away from mid-point opposite to hinges
c) In the middle
d) None of these
Explanation: None of the above
38. Water boils at a lower temperature on the hills because
a) It is cold on the hills
b) There is less carbon dioxide on the hills
c) There is a decrease in air pressure on the hills
d) There is less oxygen
Explanation: The boiling point of water is lower at higher altitudes due to the decreased atmospheric pressure. A liquid boils when its vapour pressure exceeds the local total pressure. As the atmospheric pressure drops, the Vapour pressure increases more than the local pressure at an even lower temperature.
39. The force exerted by a magnet is an example of _______
a) Non-contact force
b) Muscular force
c) Contact force
d) Electrostatic force
Explanation: The force exerted by a magnet is an example of Non-contact force.
40. A man standing close to the platform at a railway station experiences a pulling force towards a fast moving train because of ________ .
a) Gravitational force between train and man
b) Illusion of the man
c) The centripetal force
d) Pressure difference due to fast moving air in between
Explanation: When a fast-moving train passes a man standing on the platform at rest, the air between train and person also moves with greater speed. This rapidly moving air, by Bernoulli's principle will have a lower pressure than the still air a few feet away.
41. Lightning is produced when
a) Similar charges of electricity rush towards each other and then get repelled
b) Clouds strike against impurities in air and the friction burns up these impurities
c) Strong opposite charges in different clouds break down the resistance offered by the intervening air
d) Water vapour produces electricity in the clouds
Explanation: Lightning is produced when strong opposite charges in different clouds break down the resistance offered by the intervening air.
42. The metal used to make lightning conductors is
a) Iron
b) Aluminium
c) copper
d) Zinc
Explanation: The main attribute common to all lightning rods is that they are all made of conductive materials, such as copper and aluminum. Copper and its alloys are the most common materials used in lightning protection.
43. Good conductor of electricity is
a) Dry air
b) paper
c) Kerosene
d) Graphite
Explanation: Good conductor of electricity is graphite.
44. One Kilowatt hour is equal to
a) 3.6 Mega Joule
b) 3.8 Mega Joule
c) 3.2 Mega Joule
d) 4.0 Mega Joule
Explanation: One Kilowatt hour is equal to 3.6 Mega Joule.
45.Materials that usually are good conductors of electricity?
a) Aluminium
b) lead
c) Nickel
d) wood
Explanation: Aluminium is good conductors of electricity.
46. Rainbow is produced when sunlight fall on drops of rain. Which of the following physical phenomena are responsible for this ?
I. Diffusion
II. Refraction
III. Internal reflection
a) I, II and III
b) I and II
c) II and III
d) I and III
Explanation: Refraction and internal reflection are responsible for this physical phenomena.
47. Natural radioactivity was discovered by
a) Marie Curie
b) Ernest Rutherfor
c) Henri Becquerel
d) Enrico Fermi
Explanation: Natural radioactivity was discovered by Henri Becquerel
48. Planets are
a) luminous heavenly bodies revolving around a star
b) non-luminous heavenly bodies
c) luminous heavenly bodies that twinkle
d) luminous heavenly bodies that do not twinkle
Explanation: Planets are non-luminous heavenly bodies.
49. One nanometer is equal to
a) 10-6m
b) 10-8m
c) 10-9m
d) 10-5m
Explanation: One nanometer is equal to 10-9 m.
50. Mica is used in electrical appliances such as electric iron because mica is
a) a good conductor of heat but a bad conductor of electricity
b) a bad conductor of heat but a good conductor of electricity
c) a good conductor of heat as well as electricity
d) a bad conductor of heat as well as electricity
Explanation: Mica is used in electrical appliances such as electric iron because mica is a good conductor of heat but a bad conductor of electricity.
51. Sound following a flash of lightning is called
a) Stoning
b) Bolting
c) Thunder
d) Cloud clash
Explanation: Sound following a flash of lightning is called Thunder. Thunder or thunder clap always follows lightning because light travels faster than sound. Thunder is caused by the rush of air into the space, created by lightning as it travels from cloud to earth.
52. Acceptable noise level for human ear
a) 85 db
b) = 85 db
c) < 85 db
d) None of the above
Explanation: Because people can't hear all frequencies, or pitches of sound, A-weighted decibels (dBA) can be used to describe sound based on what human ears can actually hear. Sounds at or below 70 dBA are generally considered safe. Any sound at or above 85 dBA is more likely to damage your hearing over time.
53. Decibel is a term connected with :
a) air
b) water
c) sound
d) soil
Explanation: Decibel is a term connected with sound.
54. Decibel is the unit used for
a) Speed of light
b) Intensity of heat
c) Intensity of sound
d) Radio wave frequency
Explanation: Decibel is the unit used for intensity of sound.
55.The speed of sound in air depends on
a) Frequency
b) temperature
c) Wavelength
d) None of the Above
Explanation: The speed of sound in air depends on the type of gas and the temperature of the gas. On Earth, the atmosphere is composed of mostly diatomic nitrogen and oxygen, and the temperature depends on the altitude in a rather complex way.
56. Fish and other aquatic creatures can live inside a deep frozen pond because
a)Fish are cold-blooded animals
b) Ice is a bad conductor of heat
c) There will always be water just beneath the ice level
d) They can adapt themselves to live in ice
Explanation: All liquids have a boiling point and a freezing point. Underneath the frozen upper layer, the water remains in its liquid form and does not freeze. Also, oxygen is trapped beneath the layer of ice. As a result, fish and other aquatic animals find it possible to live comfortably in the frozen lakes and ponds.
57. The density of a gas is maximum at
a) Low temperature, low pressure
b) Low temperature, high pressure
c) High temperature, low pressure
d) High temperature, high pressure
Explanation: The density of gases depends upon the temperature. The higher the temperature, the more the molecules are spread out and the lower the density.
58. Lakes freeze in cold countries in winter, leaving the water underneath at
a) 0°C
b) 0°F
c) 4°C
d) 4°F
Explanation: Freezing takes place at he top of the lake this is because water colder than 4 degree celsius usually starts to expand and get less dense as it gets colder. It is the liquid with more density that settles at the bottom while the less denser floats above it.
59. A bimetal made copper and iron strips welded together is straight at room temperature. It is held vertically with iron strip towards left and copper strip towards right. If this bimetal is heated, it will
a) Remain straight
b) Bend towards right
c) Bend towards left
d) None of these
Explanation: Since the strips are welded together, the combined strip will bend towards left ( towards iron ) since copper strip will have more length than the iron strip.
60. Thermal expansion of materials arises from
a) Strong bonds
b) Thermal vibrations
c) Weak bonds
d) Asymmetry of potential energy curve
Explanation: Thermal expansion of materials arises from asymmetry of potential energy curve.
61. The number of waves per second in a sound is called ________ of that sound.
a) Velocity
b) Frequency
c) Displacement
d) Acceleration
Explanation: The number of waves per second in a sound is called frequency of that sound.
62. Sound waves do not show the phenomenon of
a) Refraction
b) Interference
c) Diffraction
d) Polarisation
Explanation: As sound waves are longitudinal waves, they don't exhibit Polarization phenomenon, which is exhibited by the transverse wave only.
63. Speed of sound is maximum in which among the following?
a) Gases
b) Vaccum
c) Liquids
d) Solids
Explanation: We know that, in solids all the particles are packed together and hence sound can travel from one to one very fast. Hence, speed of sound is maximum in solids and decreases from solids to liquids and liquids to gases. Sound can't travel through vacuum.
64. The ringing of an electric bell in an enclosed evacuated glass bell jar is not heard outside because
a) The ringing is not loud enough
b) The glass of the bell jar absorbs the sound waves
c) The bell jar is too small
d) There is no air or any other gas in the bell jar
Explanation: The ringing of an electric bell in an enclosed evacuated glass bell jar is not heard outside because there is no air or any other gas in the bell jar.
65.What is the full form of "RADAR" ?
a) Radio Detecting and Ranging
b) Region Device and Ranging
c) Radio Detect and Rangs
d) Radio Device and Ranging
Explanation: Radio Detecting and Ranging is the full form of "RADAR".
66. What is the SI unit of intensity of sound?
a) Decibel
b) Newton
c) Heartz
d) Tesla
Explanation: Decibel is the SI unit of intensity of sound.
67. Sound cannot pass through
a) water
b) steel
c) air
d) Vacuum
Explanation: Sound cannot travel through a perfect vacuum. A vacuum is an area without any air, like space. So sound cannot travel through space because there is no matter for the vibration to work in.
68. Sound waves cannot travel in
a) vucum
b) water
c) glass
d) Hydrogen gas
Explanation: Sound cannot travel through a perfect vacuum. A vacuum is an area without any air, like space. So sound cannot travel through space because there is no matter for the vibration to work in.
69. The quality or tone of a musical sound produced by a stringed instrument depends on
a) Frequency of vibration
b) Length of the strings in the instrument
c) Amplitude of vibration
d) Wave form of the sound
Explanation: The timbre or quality of a sound depends on its wave form, which varies with the number of overtones, or harmonics, that are present, their frequencies, and their relative intensities. In simple terms, timbre is what makes a particular musical sound have a different sound from another, even when they have the same pitch and loudness.
70. Which determines the frequency of a sound wave?
a) Amplitude
b) speed
c) Source
d) medium
Explanation: Amplitude determines the frequency of a sound wave.
71. The unit of noise pollution (level) is :
a) Decibel
b) Decimal
c) ppm
d) None of these
Explanation: Loudness (also called sound pressure level, or SPL) is measured in logarithmic units called decibels (dB).
72. The speed of sound travel fastest through
a) Liquid
b) Solid
c) gas
d) None of the above
Explanation: Of the three phases of matter (gas, liquid, and solid), sound waves travel the slowest through gases, faster through liquids, and fastest through solids.
73. Compressions and Rarefactions are characteristic of
a) Longitudinal waves
b) Transverse waves
c) Both A & B
d) Neither of A & B
Explanation: Compressions and Rarefactions are characteristic of longitudinal waves.
74. Least audible sound for most of the human ear is :
a) 10.0 µ bar
b) 0.0002 µ bar
c) 0.005 µ bar
d) 5.0 µ bar
Explanation: Least audible sound for most of the human ear is 0.0002 µ bar.
75.Hertz is a unit for measuring
a) Intensity of waves
b) Frequency of waves
c) Wavelength
d) Clarity of waves
Explanation: Frequency is the rate at which current changes direction per second. It is measured in hertz (Hz), an international unit of measure where 1 hertz is equal to 1 cycle per second.
76. For which of the following substances, the resistance decreases with increase in temperature?
a) Pure silicon
b) cooper
c) Nichrome
d) Platinum
Explanation: cooper
77. The S.I. unit of electric charge is :
a) Ampere
b) Coulomb
c) e.s.u
d) Kelvin
Explanation: Electric charge has the dimension electric current time. The SI derived unit of electric charge is the coulomb, which is defined as an ampere second.
78. Indicate the false statement about the resistance of a wire
a) It depends on material of wire
b) It is directly proportional to the length of wire
c) It is directly proportional to the area of cross-section of wire
d) Resistance of metallic wire increases with increase in temperature
Explanation: It is directly proportional to the area of cross-section of wire is a false statement.
79. The magnitude of current flowing between two end points of a conductor is proportional to the potential difference between them and is called as:
a) Avogadro's law
b) Rault's law
c) ohm law
d) Faraday's law
Explanation: According to Ohm’s Law, the potential difference (V) between two terminals of a current-carrying conductor is directly proportional to the current (I), flowing through it. The proportionality constant R, is the resistance of the conductor. Thus, V α I
or V = I × R
or I = V/R
or R = V/I.
80. What is the SI unit of electric current?
a) Newton
b) Joule
c) Ampere
d) watt
Explanation: SI unit of electric current is Ampere.
81. Noise is measured in
a) watt
b) REM
c) Centigrade
d) Decibel
Explanation: We measure sound intensity (also referred to as sound power or sound pressure) in units called decibels.
82. Man perceives sound vibrations in the frequency ranges of
a) 0 – 5 Hz
b) 6 – 10 Hz
c) 11 – 20 Hz
d) 20 – 20000 Hz
Explanation: Human ear perceives frequencies between 20 Hz (lowest pitch) to 20 kHz (highest pitch).
83. Instrument used to study the behaviour of a vibrating string is :
a) Barometer
b) Hydrometer
c) Hygrometer
d) Sonometer
Explanation: A Sonometer is a device for demonstrating the relationship between the frequency of the sound produced by a plucked string, and the tension, length and mass per unit length of the string.
84. Among the following materials sound travels fastest in
a) steel
b) air
c) Vacuum
d) water
Explanation: Among the following materials sound travels fastest in steel.
85.Sound becomes hazardous noise pollution at decibels?
a) Above 120 db
b) Above 80 db
c) Above 50 db
d) Above 30 db
Explanation: Sound levels are measured in decibels(dB), sound level of 80 or more dB can aptly be called noise which can cause serious hearing loss, tensions, high blood pressure, it can induce several disorders prematurely existing, such as hypertension, an increase in blood cholesterol level and is detrimental to health in other aspects when observed for more than maximum tolerable limit of 50 dB.
Hence, the correct answer is 'Above 80 dB'.
86. Which is best used as a sound absorbing material in partition walls ?
a) Stone chips
b) steel
c) Glass - wool
d) Glass pieces
Explanation: Glass wool is best used as a sound absorbing material in partition walls. This is so because glass wool do not transfer mechanical energy. These tend to be soft, flexible, low density, and with high surface area to linear area ratios.
87. Speed of sound is the greatest in :
a) water
b) air
c) glass
d) Glycerine
Explanation: Speed of sound is the greatest in glass.
88. The pitch of sound depends on its
a) Frequency
b) Intensity
c) Velocity
d) Amplitude
Explanation: Frequency
89. What apparatus is used to locate a submerged object?
a) Radar
b) sonar
c) Quasar
d) Pulsar
Explanation: Sonar (originally an acronym for Sound Navigation And Ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels.
90. A decibel is
a) A musical instrument
b) The wavelength of noise
c) A musical note
d) A measure of sound level
Explanation: Decibel (dB), unit for expressing the ratio between two physical quantities, usually amounts of acoustic or electric power, or for measuring the relative loudness of sounds. One decibel (0.1 bel) equals 10 times the common logarithm of the power ratio.
91. Ohm's law is valid in case of
a) Semiconductor
b) Conductor
c) superConductor
d) Insulator
Explanation: Ohm's law is valid in case of conductor.
92. Electrical burns occur principally because of
a) Radiation pulses of the electricity
b) The heat generated by the flow of electrical current through the body
c) The high energy of electrons
d) All of the above
Explanation: Electrical burns are among the most serious burns and require immediate medical attention. They occur when electric current flows through tissues or bone, generating heat that causes tissue damage. Arc or flash burns result from high temperatures caused by an electric arc or explosion near the body.
93. The SI unit of resistance is:
a) Newton
b) Coulomb
c) ohm
d) joule
Explanation: The SI unit of resistance is Ohm.
94. Electrical Energy is the energy of
a) protons
b) Neutrons
c) Electrons
d) All the above
Explanation: The SI unit of resistance is electrons.
95.As water is cooled from 4 deg C to 0 deg C, its density
a) Increases
b) Decreases
c) Remains same
d) None of the above
Explanation: When water is cooled from 4°C to 0°C, its density decreases.
96. If a band is played on the moon the sound will
a) Reverberate
b) Be heard by us faintly
c) Be heard upto 10km from it
d) Not be heard at any distance at all from it
Explanation: As there is no atmosphere surrounding the moon, the sound from any band that is played there cannot travel outwards there is no material medium surrounding it for its propagation.
97.The shape of our milky way galaxy is
a) Circular
b) Elliptical
c) spiral
d) None of the above
Explanation: The shape of our milky way galaxy is spiral.
98. The colours of stars depend on their
a) Temperature
b) Distance
c) Radius
d) Atmospheric pressure
Explanation: Stars come in lots of different colours, and their colour depends on the temperature of the star. We find that small stars are cool (less than 3000°C) with a red-ish appearance, whereas big heavy stars are hot (over 30,000°C), and have a blue-ish glow.
99. The substance which conducts current in the solid state is
a) Diamond
b) Graphite
c) Iodine
d) Sodium chloride
Explanation: One free electron is there due to which graphite conducts electricity in the solid state.
100. Electric current is measured by which instrument?
a) Voltmeter
b) Ammeter
c) Barometer
d) Sinometer
Explanation: The electric current in one part of a circuit is measured with an ammeter, which gives a reading in ampere.