Previous Year Physics Questions & Answers: The CRPF (Central Reserve Police Force) Radio Operator, Cipher, and Radio Fitter Exam is a highly competitive recruitment test that evaluates candidates on various subjects, including Physics. Since these roles involve technical expertise in communication and electronics, understanding fundamental physics concepts is crucial for success.
mathmetics | computer |previous year question paper
In this article, we will cover:
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The importance of Physics in the CRPF exam
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Key topics from previous years’ physics papers
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Sample questions with solutions
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Effective preparation tips
Importance of Physics in CRPF Radio Operator, Cipher & Radio Fitter Exam
Physics plays a crucial role in the CRPF Technical Examination, particularly for Radio Operator, Cipher, and Radio Fitter roles. The questions are designed to test candidates’ understanding of concepts related to electricity, magnetism, waves, optics, and mechanics, which are essential for handling communication systems and radio equipment.
The Physics section in the exam generally includes:
πΉ Electromagnetism β Electric Circuits, Magnetic Fields, Electromagnetic Induction
πΉ Waves & Sound β Frequency, Wavelength, Wave Propagation
πΉ Optics β Reflection, Refraction, Lenses, Mirrors
πΉ Mechanics β Laws of Motion, Work, Power, Energy
πΉ Thermodynamics β Heat, Temperature, Laws of Thermodynamics
Previous Year Physics Questions with Solutions
Here are some important Physics questions from previous CRPF Radio Operator, Cipher, and Radio Fitter exams:
1. Electromagnetism Question
π Q1: What is the SI unit of electrical resistance?
π‘ Solution: The SI unit of resistance is Ohm (Ξ©).
2. Wave & Sound Question
π Q2: The speed of sound is highest in which medium?
π‘ Solution: The speed of sound is highest in solids (e.g., metals) because particles are closely packed, allowing faster transmission of sound waves.
3. Optics Question
π Q3: What is the focal length of a convex lens with a power of +5D?
π‘ Solution:
Formula: Focal Length (f) = 1 / Power (P)
f = 1 / 5D = 0.2 m or 20 cm
4. Mechanics Question
π Q4: According to Newtonβs second law, force is equal to?
π‘ Solution: F = ma (Force = Mass Γ Acceleration)
5. Thermodynamics Question
π Q5: Which law of thermodynamics states that energy cannot be created or destroyed?
π‘ Solution: The First Law of Thermodynamics states that energy remains conserved; it can only be transferred or converted from one form to another.
Preparation Tips for CRPF Physics Section
π Understand the Basics β Focus on fundamental concepts like Electricity, Magnetism, and Mechanics.
π Solve Previous Year Papers β Practice old question papers to identify frequently asked topics.
π Memorize Important Formulas β Keep a formula sheet handy for quick revision.
π Use Visual Learning β Watch online videos and use diagrams for better understanding.
π Attempt Mock Tests β Regular practice through mock tests will improve speed and accuracy.
Previous Year Physics Questions & Answers
Here is the proper question-answer format starting with serial number 1, and the correct answer is provided below each question:
1. Which of the following waves cannot propagate in a vacuum?
a) Radio Waves
b) Light Waves
c) X-rays
d) Ultrasonic Waves
Answer: d) Ultrasonic Waves
2. Which one of the following statements is correct? A slab of ice kept in a room:
a) Does not radiate heat
b) Does not radiate heat but absorbs heat from the surrounding
c) Radiates heat but absorbs more heat from the surrounding
d) Radiates heat more than that absorbed by it from the surrounding
Answer: c) Radiates heat but absorbs more heat from the surrounding
3. The formula for electrical current is:
a) Voltage / Resistance
b) Resistance Γ Voltage
c) Voltage + Resistance
d) Resistance / Voltage
Answer: a) Voltage / Resistance
4. If a gas in a fixed volume container is heated, the resultant pressure on the gas:
a) Remains the same
b) Increases
c) Decreases
d) Is inversely proportional to the heat
Answer: b) Increases
5. If the current in a circuit equals 0 A, it is likely that the:
a) Voltage is too high
b) Resistance is too low
c) Circuit has a short
d) Circuit is open
Answer: d) Circuit is open
6. How many valence shell electrons are there in semiconductor atoms?
a) 16
b) 8
c) 4
d) 2
Answer: c) 4
7. An ammeter is used to measure:
a) Voltage
b) Current
c) Resistance
d) All of the above
Answer: b) Current
8. If a waveform period is determined to be 10 microseconds in duration, what is the frequency of the signal?
a) 100 Hz
b) 1000 Hz
c) 10 KHz
d) 100 KHz
Answer: d) 100 KHz
9. What is the name of a device that converts sound waves to electrical waves?
a) An amplifier
b) An antenna
c) A filter
d) A microphone
Answer: d) A microphone
10. Convert (11001001)β to decimal:
a) 201
b) 2001
c) 20
d) 210
Answer: a) 201
11. Which of the gas is not known as a greenhouse gas?
a) Methane
b) Nitrous Oxide
c) Carbon Dioxide
d) Hydrogen
Answer: d) Hydrogen
12. Permanent hardness of water may be removed by the addition of:
a) Sodium Carbonate
b) Alum
c) Potassium Permanganate
d) Lime
Answer: a) Sodium Carbonate
13. Which of the following is the lightest metal?
a) Mercury
b) Lithium
c) Lead
d) Silver
Answer: b) Lithium
14. Rectifiers are used to convert:
a) Direct current to Alternating current
b) Alternating current to Direct current
c) High voltage to Low voltage
d) Low voltage to High voltage
Answer: b) Alternating current to Direct current
15. Sound travels with a different speed in media. In what order does the velocity of sound increase in these media?
a) Water, Iron, and Air
b) Iron, Air, and Water
c) Air, Water, and Iron
d) Iron, Water, and Air
Answer: c) Air, Water, and Iron
16. The maximum number of covalent bonds formed by nitrogen is:
a) 2
b) 3
c) 4
d) 1
Answer: b) 3
17. Plants absorb dissolved nitrates from soil and convert them into:
a) Free Nitrogen
b) Urea
c) Ammonia
d) Proteins
Answer: d) Proteins
18. Oβ released in the process of photosynthesis comes from:
a) COβ
b) Water
c) Sugar
d) Pyruvic Acid
Answer: b) Water
19. Decibel is the unit used for:
a) Speed of Light
b) Intensity of Heat
c) Intensity of Sound
d) Radio Wave Frequency
Answer: c) Intensity of Sound
20. Anaemia is caused in man due to the deficiency of:
a) Folic Acid
b) Vitamin A
c) Vitamin B12
d) None
Answer: c) Vitamin B12
21. Which of the following is a term related to scanners?
a) Laser
b) TWAIN
c) Cartridge
d) Media
Answer: b) TWAIN
22. The most flexibility in how devices are wired together is provided by:
a) Bus Networks
b) Star Networks
c) Ring Networks
d) T-Switched Networks
Answer: b) Star Networks
23. What is the maximum data capacity for optical fiber cable?
a) 10 Mbps
b) 100 Mbps
c) 1000 Mbps
d) 10000 Mbps
Answer: d) 10000 Mbps
24. Which one of the following is a search engine?
a) Netscape
b) Java
c) AltaVista
d) Internet
Answer: c) AltaVista
25. The unit of Inductance is:
a) Volt
b) Henry
c) Weber
d) Ohm
Answer: b) Henry
Here is the proper question-answer format starting with serial number 26, and the correct answer is provided below each question:
26. Which of the following gases cause global warming?
a) Oxygen
b) Carbon dioxide
c) Nitrogen
d) Chlorine
Answer: b) Carbon dioxide
27. Hydrogen is considered a good fuel because:
a) Its calorific value is high
b) Its burning does not cause pollution
c) Both (a) & (b)
d) None of these
Answer: c) Both (a) & (b)
28. The sun is visible to us a little before the actual sunrise and a little after the actual sunset because of:
a) Diffraction
b) Scattering
c) Refraction
d) Reflection
Answer: c) Refraction
29. Light travels fastest in:
a) Vacuum
b) Glass
c) Air
d) Iron
Answer: a) Vacuum
30. Rusting of Iron is an example of:
a) Reduction
b) Oxidation
c) Both (a) & (b)
d) Displacement reaction
Answer: b) Oxidation
31. Which of the following is a non-metal that remains liquid at room temperature?
a) Phosphorous
b) Bromine
c) Chlorine
d) Helium
Answer: b) Bromine
32. Quartz crystals normally used in quartz clocks, etc., are chemically:
a) Silicon dioxide
b) Germanium oxide
c) A mixture of germanium oxide and silicon dioxide
d) Sodium silicate
Answer: a) Silicon dioxide
33. The hardest substance available on Earth is:
a) Gold
b) Iron
c) Diamond
d) Platinum
Answer: c) Diamond
34. What is laughing gas?
a) Nitrous Oxide
b) Carbon monoxide
c) Sulphur dioxide
d) Hydrogen peroxide
Answer: a) Nitrous Oxide
35. Production of chlorofluorocarbons (CFC) gas, which is proposed to be banned in India, is used in which of the following domestic products?
a) Television
b) Refrigerator
c) Tube light
d) Cooking gas
Answer: b) Refrigerator
36. An atom’s atomic number is determined by the number of:
a) Electrons
b) Neutrons & protons
c) Neutrons
d) Protons
Answer: d) Protons
37. A voltage will influence current only if the circuit is:
a) Open
b) Insulated
c) Closed
d) High resistance
Answer: c) Closed
38. Primary batteries, unlike secondary batteries, may be:
a) Charged once
b) Used once
c) Stored indefinitely
d) Recharged over & over
Answer: b) Used once
39. A voltmeter is used:
a) To measure current
b) In series with the circuit
c) In parallel with the circuit
d) To measure coulombs
Answer: c) In parallel with the circuit
40. An example of potential energy is:
a) A battery
b) The sun
c) A moving vehicle
d) Tea-kettle steam
Answer: a) A battery
41. A switch is a device that:
a) Holds a fuse
b) Short circuits complex circuits
c) Has double poles
d) Opens or completes a current path
Answer: d) Opens or completes a current path
42. Which electronics material opposes the movement of free electrons?
a) Conductor
b) Insulator
c) Semiconductor
d) Element
Answer: b) Insulator
43. A short circuit will have:
a) No current flow
b) Some current flow
c) A small current flow
d) A large current flow
Answer: d) A large current flow
44. What happens to total resistance in a circuit with parallel resistors if one of them opens?
a) It increases
b) It halves
c) It decreases
d) It remains the same
Answer: a) It increases
45. What is the total resistance of four 1 kΞ© parallel-connected resistors?
a) 200 ohms
b) 250 ohms
c) 400 ohms
d) 4 kilohms
Answer: b) 250 ohms
46. Zener diode is mostly used as:
a) Rectifier
b) Voltage regulator
c) Clipper
d) Voltage divider
Answer: b) Voltage regulator
47. Transformer works on the principle of:
a) Mutual induction
b) Static induction
c) Stray capacitance
d) EM radiation
Answer: a) Mutual induction
48. Resistance is directly proportional to the:
a) Voltage
b) Current
c) Temperature
d) Inductance
Answer: c) Temperature
49. Semiconductor atom has __ valence electron.
a) 1
b) 2
c) 3
d) 4
Answer: d) 4
50. Atomic number of copper is:
a) 26
b) 27
c) 28
d) 29
Answer: d) 29
Here is the proper question-answer format starting with serial number 51, and the correct answer is provided below each question:
51. Farad is the unit of:
a) Resistance
b) Conductance
c) Capacitance
d) Inductance
Answer: c) Capacitance
52. Which of the following remains constant while throwing a ball upward?
a) Displacement
b) Kinetic Energy
c) Acceleration
d) Velocity
Answer: c) Acceleration
53. The working principle of a washing machine is:
a) Centrifugation
b) Dialysis
c) Reverse Osmosis
d) Diffusion
Answer: a) Centrifugation
54. A jet engine works on the principle of conservation of:
a) Linear Momentum
b) Angular Momentum
c) Energy
d) Mass
Answer: a) Linear Momentum
55. Ball bearings are used in bicycles, cars, etc., because:
a) The actual area of contact between the wheel and axle is increased.
b) The effective area of contact between the wheel and axle is increased.
c) The effective area of contact between the wheel and axle is reduced.
d) None of the statements is correct.
Answer: c) The effective area of contact between the wheel and axle is reduced.
56. In a cricket match, while catching a fast-moving ball, a fielder in the ground gradually pulls his hand backward with the moving ball to reduce the velocity to zero. The act represents:
a) Newtonβs First Law of Motion
b) Newtonβs Second Law of Motion
c) Newtonβs Third Law of Motion
d) Law of Conservation of Energy
Answer: b) Newtonβs Second Law of Motion
57. Match Column I and Column II:
Column I
A) Electric Motor
B) Electric Bell
C) Electric Bulb
D) Photoelectric Cell
E) Steam Engine
Column II
P) Electric energy to Sound Energy
Q) Electric energy to Mechanical Energy
R) Light energy to Electrical Energy
S) Heat energy to Light Energy
T) Electric energy to Light Energy
a) A-P, B-Q, C-T, D-R, E-S
b) A-Q, B-P, C-T, D-T, E-S
c) A-Q, B-P, C-T, D-S, E-R
d) A-Q, B-P, C-T, D-R, E-S
Answer: d) A-Q, B-P, C-T, D-R, E-S
58. The tendency of a liquid drop to contract and occupy a minimum area is due to:
a) Surface Tension
b) Viscosity
c) Density
d) Vapor Pressure
Answer: a) Surface Tension
59. When pressure is exerted on an enclosed liquid or gas at rest, it is transmitted equally in all directions. This is in accordance with:
a) Boyleβs Law
b) Pascalβs Law
c) Archimedesβ Principle
d) Principle of Flotation
Answer: b) Pascalβs Law
60. The specific gravity of a substance is measured by a hydrometer at sea level. If the measurement is done at the top of a mountain, what would be the specific gravity?
a) Zero
b) More than that measured at sea level
c) Less than that measured at sea level
d) Same as that measured at sea level
Answer: d) Same as that measured at sea level
61. Which one of the following is not electromagnetic in nature?
a) Cathode-ray
b) X-ray
c) Gamma rays
d) Infrared rays
Answer: a) Cathode-ray
62. From a power station, the power is transmitted at a very high voltage because:
a) It is generated only at high voltage
b) It is cheaper to produce electricity at high voltage
c) Electricity at high voltage is less dangerous
d) There is less loss of energy in transmission at high voltage
Answer: d) There is less loss of energy in transmission at high voltage
63. Conductivity increases in the order of:
a) Al, Ag, Cu
b) Al, Cu, Ag
c) Cu, Al, Ag
d) Ag, Cu, Al
Answer: b) Al, Cu, Ag
64. Transformers are used:
a) In DC circuits only
b) In AC circuits only
c) In both DC and AC circuits
d) Neither in DC nor in AC circuits
Answer: b) In AC circuits only
65. Consider the following statements regarding a motor car battery:
1) The voltage is usually 12 V
2) Electrolyte used is hydrochloric acid
3) Electrodes are lead and copper
4) Capacity is expressed in ampere-hour
Which of the following statements are correct?
a) 1 and 2
b) 2 and 3
c) 3 and 4
d) 1 and 4
Answer: d) 1 and 4
66. Which one among the following is the correct order of power consumption for light of equal intensity?
a) CFL tube < Fluorescent tube < Incandescent bulb < Light-emitting Diode
b) Light-emitting Diode < CFL tube < Fluorescent tube < Incandescent bulb
c) CFL tube < Fluorescent tube < Light-emitting Diode < Incandescent bulb
d) Incandescent bulb < Light-emitting Diode < Fluorescent tube < CFL tube
Answer: b) Light-emitting Diode < CFL tube < Fluorescent tube < Incandescent bulb
67. Two pieces of metallic wire having equal lengths and equal volumes placed in air have different resistance. The two wires must:
a) Have different cross-sections
b) Have different temperatures
c) Be of different materials
d) Be of the same density
Answer: c) Be of different materials
68. Which of the following cannot be fabricated on an IC?
a) Transistors
b) Inductors and transformers
c) Diodes
d) Resistors
Answer: b) Inductors and transformers
69. The waves used in telecommunication are:
a) Infrared
b) Ultraviolet
c) Microwave
d) Cosmic rays
Answer: c) Microwave
70. Repeaters used in telephone links are:
a) Rectifiers
b) Oscillators
c) Amplifiers
d) Transformers
Answer: c) Amplifiers
71. Which one among the following radiations carries maximum energy?
a) Ultraviolet rays
b) Gamma rays
c) X-rays
d) Infrared rays
Answer: b) Gamma rays
72. Fluorescent tubes are fitted with a choke. The choke coil:
a) Steps up the line voltage
b) Steps down the line voltage
c) Reduces current in the circuit
d) Chokes low-frequency current
Answer: c) Reduces current in the circuit
73. Why are the inner linings of hot water geysers made up of copper?
a) Copper has low heat capacity
b) Copper has high electrical conductivity
c) Copper does not react with steam
d) Copper is a good conductor of both heat and electricity
Answer: d) Copper is a good conductor of both heat and electricity
74. Which zone of a candle flame is the hottest?
a) Dark innermost zone
b) Outermost zone
c) Middle luminous zone
d) Central zone
Answer: b) Outermost zone
75. Three bulbs of 40 W, 60 W, and 100 W are connected in series to a current source of 200 V. Which of the following statements is true?
a) 40 W bulb glows brightest
b) 60 W bulb glows brightest
c) 100 W bulb glows brightest
d) All bulbs glow with the same brightness
Answer: a) 40 W bulb glows brightest
Here is the proper question-answer format starting with serial number 76, and the correct answer is provided below each question:
76. A continuous flow of electrons is called:
a) Current
b) Conductor
c) Resistance
d) Potential Difference
Answer: a) Current
77. A charge produced due to the gain of an electron is:
a) Positive charge
b) Negative charge
c) Neutral
d) Heating energy
Answer: b) Negative charge
78. What is the electric potential of the earth?
a) One
b) Two
c) Four
d) Zero
Answer: d) Zero
79. Ohmβs law is valid for:
a) Conductor only
b) Semiconductor only
c) Insulator only
d) Resistance only
Answer: a) Conductor only
80. If a bulb is taken out of a parallel circuit:
a) The other bulb will go out as well
b) The other bulb will continue to glow
c) None of the above
d) Either (a) or (b)
Answer: b) The other bulb will continue to glow
81. The core of a strong electromagnet consists of:
a) Steel
b) Copper
c) Lead
d) Soft iron
Answer: d) Soft iron
82. During a short circuit, the current in the circuit:
a) Reduces
b) Remains the same
c) Increases heavily
d) Varies continuously
Answer: c) Increases heavily
83. A fuse is a small piece of wire generally prepared from an alloy of:
a) Tin and copper
b) Tin and lead
c) Tin and aluminium
d) Tin and iron
Answer: b) Tin and lead
84. Which of the following is renewable energy?
a) Nuclear energy
b) Fossil energy
c) Wind energy
d) Hydro energy
Answer: c) Wind energy
85. The component of solar radiation that carries heat with it is:
a) Infrared radiation
b) Ultraviolet radiation
c) Photons
d) Quantum
Answer: a) Infrared radiation
86. β¦β¦β¦β¦β¦.. is natural gas produced from waste products.
a) Nitrogen gas
b) Gasohol
c) Hydrogen gas
d) Biogas
Answer: d) Biogas
87. The energy of moving wind is called:
a) Kinetic
b) Light
c) Heat
d) Potential
Answer: a) Kinetic
88. The formula for electrical current is:
a) Voltage / Resistance
b) Resistance Γ Voltage
c) Voltage + Resistance
d) Resistance / Voltage
Answer: a) Voltage / Resistance
89. The energy stored in petrol is:
a) Mechanical
b) Chemical
c) Heat
d) All of the above
Answer: b) Chemical
90. If the current in a circuit equals 0, it is likely that the:
a) Voltage is too high
b) Resistance is too low
c) Circuit has a short
d) Circuit is open
Answer: d) Circuit is open
91. Abiotic factors do not include:
a) Bacteria
b) Soil
c) Temperature
d) Water
Answer: a) Bacteria
92. Plants are also called:
a) Decomposers
b) Heterotrophs
c) Autotrophs
d) Scavengers
Answer: c) Autotrophs
93. Ozone is a molecule formed by how many oxygen atoms?
a) 2
b) 3
c) 1
d) 4
Answer: b) 3
94. Light travels in a straight line because:
a) It consists of small particles
b) Light is reflected by the surroundings
c) The wavelength of light is very small
d) All of the above
Answer: c) The wavelength of light is very small
95. How does a mirror work?
a) By reflecting the light
b) By absorbing the light
c) By transmitting the light
d) All of the above
Answer: a) By reflecting the light
96. An ENT specialist uses a β¦β¦β¦β¦β¦.. mirror for the examination of the ear, nose, and throat.
a) Convex
b) Concave
c) Plane
d) Either (b) or (c)
Answer: b) Concave
97. When light passes from one medium to another, the characteristic that remains unaffected is:
a) Speed
b) Direction
c) Wavelength
d) Frequency
Answer: d) Frequency
98. Which is an expanded form of DNA?
a) Deoxyribose nucleic acid
b) Dichloro-nucleic acid
c) Dichloro nitric acid
d) Denitrified nucleic acid
Answer: a) Deoxyribose nucleic acid
99. The wings of a bird and butterfly are:
a) Vestigial organs
b) Homologous organs
c) Analogous organs
d) None of these
Answer: c) Analogous organs
100. Light travels faster in:
a) Vacuum
b) Glass
c) Air
d) Iron
Answer: a) Vacuum
Here is the proper question-answer format starting with serial number 101, and the correct answer is provided below each question:
101. Thermistors work on the principle of:
a) Resistance varies with temperature
b) Voltage varies with temperature
c) Current varies with temperature
d) Temperature varies with voltage
Answer: a) Resistance varies with temperature
102. Transformers work on the principle of:
a) Mutual Inductance
b) Magnetism
c) Ohm’s Law
d) Resonance
Answer: a) Mutual Inductance
103. The current flowing through a wire is 9 amperes, and the resistance is 7 ohms for 1 minute. Find the heat loss in kcal.
a) 9.4
b) 8.1
c) 10
d) 11
Answer: b) 8.1
104. The SI unit of conductivity is:
a) ohm/m
b) ohm/mΒ²
c) mho/mΒ²
d) siemens/m
Answer: d) siemens/m
105. What is the purpose of a choke in a tube light?
a) High current on filaments
b) Gives high voltage at filaments
c) Gives both high voltage and current at filaments
d) None of these
Answer: b) Gives high voltage at filaments
106. The SI unit of magnetic flux is:
a) Weber
b) Weber/mΒ²
c) Volt-seconds/mΒ²
d) Volt ampere/m
Answer: a) Weber
107. Two charged bodies having equal potential are connected:
a) Current will flow
b) Current will not flow
c) Current will flow if a resistor is connected
d) Canβt say
Answer: b) Current will not flow
108. Which of the following represents the relation between charge (Q), potential difference (V), and work done (W)?
a) V = W Γ Q
b) W = V / Q
c) V = Q / W
d) V = W / Q
Answer: d) V = W / Q
109. The voltmeter is always connected in ___ across the points along which potential difference is to be measured.
a) Series
b) Parallel
c) Either series or parallel
d) None of these
Answer: b) Parallel
110. An electric fuse works on the principle of:
a) Chemical effect of the current
b) Heating effect of the current
c) Magnetic effect of the current
d) None of these
Answer: b) Heating effect of the current
111. On which of the following is no plus or minus sign marked?
a) Battery
b) Voltmeter
c) Ammeter
d) Resistor
Answer: d) Resistor
112. An electric charge in uniform motion produces:
a) Electric field only
b) Magnetic field only
c) Both electric and magnetic fields
d) No such field at all
Answer: c) Both electric and magnetic fields
113. A current is passed through a straight wire. The magnetic field established around it has its line of force:
a) Circular and endless
b) Oval in shape and endless
c) Straight lines
d) All of the above
Answer: a) Circular and endless
114. The core of an electromagnet is made of:
a) Nickel
b) Steel
c) Copper
d) Soft iron
Answer: d) Soft iron
115. The unit of the electric field is:
a) Volts per mΒ²
b) Coulomb per mΒ²
c) Newton per coulomb
d) Newton volt per meter
Answer: c) Newton per coulomb
116. Copper contains _ electrons.
a) 24
b) 26
c) 27
d) 29
Answer: d) 29
117. The resistivity of a wire depends on:
a) Length
b) Material
c) Cross-sectional area
d) None of the above
Answer: b) Material
118. The resistance of a wire is r ohms. The wire is stretched to double its length. Then its resistance in ohms is:
a) r / 2
b) 4 r
c) 2 r
d) r / 4
Answer: b) 4 r
119. Kirchhoff’s second law is based on the law of conservation of:
a) Charge
b) Energy
c) Momentum
d) Mass
Answer: b) Energy
120. Two bulbs marked 200 watt-250 volts and 100 watt-250 volts are joined in series to a 250-volt supply. The power consumed in the circuit is:
a) 33 watt
b) 67 watt
c) 100 watt
d) 300 watt
Answer: b) 67 watt
121. Ampere-second could be the unit of:
a) Power
b) Conductance
c) Energy
d) Charge
Answer: d) Charge
122. An electric current of 5 A is the same as:
a) 5 J / C
b) 5 V / C
c) 5 C / sec
d) 5 W / sec
Answer: c) 5 C / sec
123. A circuit contains two unequal resistances in parallel:
a) Current is the same in both
b) Large current flows in the larger resistor
c) Potential difference across each is the same
d) Smaller resistance has smaller conductance
Answer: c) Potential difference across each is the same
124. The conductivity of a good conductor _ with temperature.
a) Increases
b) Decreases
c) Canβt say
d) None of the above
Answer: b) Decreases
125. Four wires of the same material, the same cross-sectional area, and the same length, when placed in parallel, give a total resistance of 0.25 ohms. If the same four wires are connected in series, find the effective resistance.
a) 1 ohm
b) 2 ohm
c) 4 ohm
d) 8 ohm
Answer: c) 4 ohm
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