এই post-এ আমরা আপনাদের জন্য নিয়ে এসেছি WBCS Preliminary Previous Year Physics Questions with Answers (2000–2023) — যেখানে সমস্ত Physics PYQ গুলি এক জায়গায় Year Wise এবং exam-oriented ভাবে দেওয়া হয়েছে, সাথে রয়েছে Correct Answers।
WBCS Preliminary Previous Year Physics Questions with Answers (2000–2023)
Below is the complete list of Physics questions asked in WBCS Prelims from 2000 up to 2023 with answers.
Q. 1) For a floating body to be in stable equilibrium, where should its centre of buoyancy be located?
(WBCS Preliminary Exam: 2023)
A) At the centre of gravity
B) Above the centre of gravity
C) Below the centre of gravity
D) It may anywhere
Correct Answer: (B) Above the centre of gravity
Q. 2) An iron ball is heated. The percentage increase will be largest in
(WBCS Preliminary Exam: 2023)
A) density
B) surface area
C) diameter
D) volume
Correct Answer: (D) volume
Q. 3) A drop of water is broken into two drops. The sum of which property of the drops is equal to that of the single one?
(WBCS Preliminary Exam: 2023)
A) Radius
B) Surface area
C) Surface energy
D) Volume
Correct Answer: (D) Volume
Q. 5) Combine three resistors 5Ω, 4.5Ω and 3Ω in such a way that the total resistance of this combination is maximum with value
(WBCS Preliminary Exam: 2023)
A) 12.5 Ω
B) 13.5 Ω
C) 14.5 Ω
D) 16.5 Ω
Correct Answer: (A) 12.5 Ω
Q. 6) A bird is sitting in a wire cage hanging from the spring balance (W1). If the bird flies about inside (W2), which is true?
(WBCS Preliminary Exam: 2023)
A) W1 > W2
B) W1 < W2
C) W1 = W2
D) W1 = 1/W2
Correct Answer: (A) W1 > W2
Q. 7) The density of water at 20°C is 998 and 40°C is 992. The coefficient of the cubical expansion is:
(WBCS Preliminary Exam: 2023)
A) 2 × 10⁻⁴ °C⁻¹
B) 6 × 10⁻⁴ °C⁻¹
C) 3 × 10⁻⁴ °C⁻¹
D) 4 × 10⁻⁴ °C⁻¹
Correct Answer: (C) 3 × 10⁻⁴ °C⁻¹
Q. 8) The efficiency of a Carnot engine working between 227°C and 27°C is
(WBCS Preliminary Exam: 2023)
A) 100%
B) 50%
C) 40%
D) 20%
Correct Answer: (C) 40%
Q. 9) The radiation carrying maximum energy –
(WBCS Preliminary Exam: 2022)
A) UV rays
B) Gamma rays
C) X-rays
D) IR rays
Correct Answer: (B) Gamma rays
Q. 10) Which quantity is increased in step-down transformer?
(WBCS Preliminary Exam: 2022)
A) Voltage
B) Current
C) Wattage
D) Frequency
Correct Answer: (B) Current
Q. 11) A particle is moving in uniform circular motion with constant speed V along radius r. The acceleration is:
(WBCS Preliminary Exam: 2022)
A) Zero
B) v/r
C) v/r²
D) v²/r
Correct Answer: (D) v²/r
Q. 12) A boat floating in a tank carries passengers. If they drink water from the tank, the water level will:
(WBCS Preliminary Exam: 2021)
A) It will go down.
B) It will rise.
C) It will depend on pressure.
D) It will remain same.
Correct Answer: (D) It will remain same.
Q. 13) Pure silicon at 0 K is
(WBCS Preliminary Exam: 2021)
A) semiconductor
B) metal
C) insulator
D) superconductor
Correct Answer: (C) insulator
Q. 14) Ratio of the rms speed and the most probable speed for molecules in an ideal gas is
(WBCS Preliminary Exam: 2021)
A) √3 : 2
B) 1 : √3
C) √3 : √2
D) √2 : √3
Correct Answer: (C) √3 : √2
Q. 16) The freezing chest in refrigerator is kept near the top because
(WBCS Preliminary Exam: 2021)
A) it is convenient to use
B) it reduces cost
C) conduction cooling
D) convection currents are set up
Correct Answer: (D) convection currents are set up
Q. 17) The solar cooker works on the same principle as
(WBCS Preliminary Exam: 2021)
A) Bolometer
B) Pyrometer
C) Greenhouse
D) Solar PV cell
Correct Answer: (C) Greenhouse
Q. 18) In terms of thermal conductivity (k) and electrical conductivity (δ), diamond has
(WBCS Preliminary Exam: 2021)
A) low k and high δ
B) high k and low δ
C) high k and high δ
D) low k and low δ
Correct Answer: (B) high k and low δ
Q. 19) A battery has 10 cells (1V each). If 2 cells are wrongly connected, the emf becomes
(WBCS Preliminary Exam: 2021)
A) 8V
B) 10V
C) 6V
D) 12V
Correct Answer: (C) 6V
Q. 20) The binary equivalent of decimal number 4.625 is
(WBCS Preliminary Exam: 2021)
A) 100.001
B) 100.11
C) 100.101
D) 100.011
Correct Answer: (C) 100.101
Q. 21) A person on a swing stands up. The time period of the swing
(WBCS Preliminary Exam: 2021)
A) increases
B) remains the same
C) decreases
D) becomes zero
Correct Answer: (C) decreases
Q. 22) The power of a lens is +2.0D. The focal length and nature are
(WBCS Preliminary Exam: 2021)
A) 50 cm, concave
B) 50 cm, convex
C) 100 cm, convex
D) 100 cm, concave
Correct Answer: (B) 50 cm, convex
Q. 23) A heavy body and a light body have equal kinetic energy. Then
(WBCS Preliminary Exam: 2021)
A) heavy body has greater momentum
B) light body has greater momentum
C) both have equal momentum
D) both have same angular momentum
Correct Answer: (A) heavy body has greater momentum
Q. 24) The spectrum of color in Compact Disc (CD) is due to
(WBCS Preliminary Exam: 2021)
A) Refraction
B) Reflection
C) Diffraction
D) Polarization
Correct Answer: (C) Diffraction
Q. 25) A pendulum clock taken to the moon will run
(WBCS Preliminary Exam: 2021)
A) at correct rate
B) 6 times faster
C) √6 times faster
D) √6 times slower
Correct Answer: (D) √6 times slower
Q. 27) The waves produced by motor boat sailing on water are
(WBCS Preliminary Exam: 2021)
A) transverse
B) longitudinal
C) longitudinal and transverse
D) stationary
Correct Answer: (C) longitudinal and transverse
Q. 28) Dilatometer is used for the measurement of
(WBCS Preliminary Exam: 2021)
A) electrical energy
B) mechanical energy
C) dimensional change in material
D) thermal energy
Correct Answer: (C) dimensional change in material
Q. 29) Sir C. V. Raman was awarded Nobel Prize for work connected with
(WBCS Preliminary Exam: 2020)
A) Scattering
B) Diffraction
C) Interference
D) Polarization
Correct Answer: (A) Scattering
Q. 30) Identify the vector quantity from the following:
(WBCS Preliminary Exam: 2020)
A) Heat
B) Angular momentum
C) Time
D) Work
Correct Answer: (B) Angular momentum
Q. 31) Nuclear sizes are expressed in a unit named
(WBCS Preliminary Exam: 2020)
A) Fermi
B) Angstrom
C) Newton
D) Tesla
Correct Answer: (A) Fermi
Q. 32) Superconductors are substances which
(WBCS Preliminary Exam: 2020)
A) conduct at lower temp
B) high resistance
C) offer no resistance
D) conduct at high temp
Correct Answer: (C) offer no resistance to the flow of current
Q. 33) Speed of sound is the maximum In
(WBCS Preliminary Exam: 2020)
A) vacuum
B) gases
C) liquids
D) solids
Correct Answer: (D) solids
Q. 34) Radiocarbon dating technique is used to estimate the age of
(WBCS Preliminary Exam: 2020)
A) rocks
B) monuments
C) soil
D) fossils
Correct Answer: (D) fossils
Q. 35) The absorption of ink by blotting paper involves
(WBCS Preliminary Exam: 2020)
A) viscosity
B) capillary action
C) diffusion
D) siphon action
Correct Answer: (B) capillary action
Q. 36) TV remote control uses
(WBCS Preliminary Exam: 2020)
A) Infrared frequency
B) Radio frequency
C) Visible frequency
D) Ultraviolet frequency
Correct Answer: (A) Infrared frequency
Q. 38) Good absorbers of heat are
(WBCS Preliminary Exam: 2019)
A) poor emitters
B) non-emitters
C) good emitters
D) highly polished
Correct Answer: (C) good emitters
Q. 39) Ventilators are provided at the top of the room
(WBCS Preliminary Exam: 2019)
A) to bring oxygen
B) for sunlight
C) maintain convection currents
D) outlet for CO2
Correct Answer: (C) to maintain convectional currents
Q. 40) Voice of your friend can be recognized by its
(WBCS Preliminary Exam: 2019)
A) pitch
B) quality
C) intensity
D) velocity
Correct Answer: (B) quality
Q. 41) Light year is
(WBCS Preliminary Exam: 2019)
A) light emitted in 1 yr
B) time from Sun to Earth
C) distance light travels in 1 yr
D) time for Earth orbit
Correct Answer: (C) distance travelled by light in free space in one year
Q. 42) Twinkling of stars is on account of
(WBCS Preliminary Exam: 2019)
A) storms in air
B) rotation of earth
C) large size
D) fluctuations in air density
Correct Answer: (D) distance and fluctuations in air density
Q. 43) Two cars passing at high speed danger side-swiping because
(WBCS Preliminary Exam: 2019)
A) increase in pressure
B) decrease in velocity
C) decrease in air pressure
D) increase in velocity
Correct Answer: (C) decrease in air pressure between them
Q. 44) Noise pollution is created if noise is in excess to
(WBCS Preliminary Exam: 2019)
A) 70-75 dB
B) 50-60 dB
C) 80-99 dB
D) 40-65 dB
Correct Answer: (C) 80-99 dB
Q. 45) At magnetic poles, the angle of dip is
(WBCS Preliminary Exam: 2019)
A) 45°
B) 30°
C) Zero
D) 90°
Correct Answer: (D) 90°
Q. 46) All electromagnetic wave have the same
(WBCS Preliminary Exam: 2018)
A) Frequency
B) amplitude
C) wavelength in vacuum
D) speed in vacuum
Correct Answer: (d) speed in vacuum
Q. 47) The speed of sound is faster in
(WBCS Preliminary Exam: 2018)
A) solids
B) liquids
C) gases
D) vacuum
Correct Answer: (a) solids
Q. 49) Short-sight defect could be corrected by a
(WBCS Preliminary Exam: 2018)
A) Convex lens
B) Concave Lens
C) Converging lens
D) None
Correct Answer: (b) Concave Lens
Q. 50) Red + Green + Blue = ?
(WBCS Preliminary Exam: 2018)
A) White
B) Black
C) Maroon
D) Blue
Correct Answer: (a) White
Q. 51) A combination of 16 bits is called
(WBCS Preliminary Exam: 2018)
A) word
B) nibble
C) memory block
D) byte
Correct Answer: (a) word
Q. 52) A stone tied to string revolves; rope snaps. The stone:
(WBCS Preliminary Exam: 2018)
A) flies off tangentially
B) moves radially out
C) moves radially in
D) None
Correct Answer: (a) The stone flies off tangentially
Q. 53) A body floating in liquid is taken to moon. The body:
(WBCS Preliminary Exam: 2018)
A) float as before
B) greater part immersed
C) lesser part immersed
D) will sink
Correct Answer: (a) will continue to float as before
Q. 54) USB is which type of storage device?
(WBCS Preliminary Exam: 2018)
A) Primary
B) Secondary
C) Tertiary
D) None
Correct Answer: (b) Secondary
Q. 55) Which is commonly used language in Android applications?
(WBCS Preliminary Exam: 2018)
A) Java
B) C++
C) C
D) PHP
Correct Answer: (a) Java
Q. 56) Errors in computer programme is called
(WBCS Preliminary Exam: 2018)
A) Spam
B) Follies
C) Virus
D) Bugs
Correct Answer: (d) Bugs
Q. 57) 1 nm is equivalent to
(WBCS Preliminary Exam: 2017)
A) 10 A
B) 100 A
C) 10 micron
D) 01 mm A
Correct Answer: (A) 10 A
Q. 58) RADAR stands for
(WBCS Preliminary Exam: 2017)
A) Radio Detection and Ranging
B) Ready Advanced Appliance
C) Range Detection Appliance
D) Ready Advanced Airplane
Correct Answer: (A) Radio Detection and Ranging
Q. 60) Shaving brush hairs drawn together out of water due to
(WBCS Preliminary Exam: 2017)
A) surface tension
B) viscosity
C) elasticity
D) temp difference
Correct Answer: (A) surface tension of water
Q. 61) Red is used as a danger signal because
(WBCS Preliminary Exam: 2017)
A) blood is red
B) scattered least
C) easily available
D) soothing for eye
Correct Answer: (B) red light is scattered least by air molecules
Q. 62) The immersed portion of pure ice floating on water is
(WBCS Preliminary Exam: 2017)
A) 8/9th
B) 9/10th
C) 10/12th
D) 11/12th
Correct Answer: (D) 11/12th of volume
Q. 63) The electric appliances in a house are connected
(WBCS Preliminary Exam: 2017)
A) in series
B) in parallel
C) either
D) both
Correct Answer: (B) in parallel
Q. 64) X-rays are
(WBCS Preliminary Exam: 2016)
A) EM short wavelength
B) beams of electrons
C) EM long wavelength
D) visible
Correct Answer: (A) electromagnetic radiations of very short wavelength
Q. 65) Astronomy means study of the —
(WBCS Preliminary Exam: 2016)
A) Moon
B) Stars
C) Sky
D) Sun
Correct Answer: (B) Stars
Q. 66) Water rises up a capillary tube because of—
(WBCS Preliminary Exam: 2016)
A) Elasticity
B) Surface tension
C) Viscosity
D) density
Correct Answer: (B) Surface tension
Q. 67) The image formed by a plane mirror is —
(WBCS Preliminary Exam: 2016)
A) real and erect
B) virtual and inverted
C) virtual and erect
D) real and inverted
Correct Answer: (C) virtual and erect
Q. 68) The energy radiated by the Sun is because of—
(WBCS Preliminary Exam: 2016)
A) Nuclear fusion
B) Nuclear fission
C) Radioactive decay
D) Photo-electric effect
Correct Answer: (A) Nuclear fusion
Q. 69) With increase in temperature resistance of pure semiconductor
(WBCS Preliminary Exam: 2016)
A) first increases
B) remains same
C) increases
D) decreases
Correct Answer: (D) decreases
Q. 70) Which of the following is not a conservative force ?
(WBCS Preliminary Exam: 2016)
A) Gravitational force
B) Frictional force
C) Electrostatic force
D) Magneto static force
Correct Answer: (B) Frictional force
Q. 72) The solar cooker works on the same principle as
(WBCS Preliminary Exam: 2015)
A) Bolometer
B) Pyrometer
C) Greenhouse
D) Galvanometer
Correct Answer: (C) Greenhouse
Q. 73) Hydraulic press is based on
(WBCS Preliminary Exam: 2015)
A) Archimedes’ law
B) Pascal’s law
C) Reynold’s law
D) Bernouli law
Correct Answer: (B) Pascal’s law
Q. 74) LED stands for
(WBCS Preliminary Exam: 2015)
A) Light emitting device
B) Light emitting diode
C) light encapsulated
D) light emitting dots
Correct Answer: (B) Light emitting diode
Q. 75) At what temperature, Celsius and Fahrenheit are same ?
(WBCS Preliminary Exam: 2015)
A) + 40°
B) + 20°
C) – 20°
D) – 40°
Correct Answer: (D) – 40°
Q. 76) When a ball is taken from equator to the pole
(WBCS Preliminary Exam: 2015)
A) mass increases
B) both change
C) weight increases
D) weight decreases
Correct Answer: (C) Its weight increases
Q. 77) Satellites provide information about
(WBCS Preliminary Exam: 2015)
A) Forest cover
B) Rivers
C) Storms
D) All of above
Correct Answer: (D) All of the above
Q. 78) Compound microscope has
(WBCS Preliminary Exam: 2014)
A) two lenses
B) requires UV light
C) only dead organisms
D) large room space
Correct Answer: (A) two lenses
Q. 79) Among the following select the odd one
(WBCS Preliminary Exam: 2014)
A) Metre
B) Furlong
C) Acre
D) Mile
Correct Answer: (C) Acre (Unit of Area)
Q. 80) Which of the rays is most dangerous ?
(WBCS Preliminary Exam: 2014)
A) Alpha ray
B) Beta ray
C) Gamma ray
D) X-ray
Correct Answer: (C) Gamma ray
Q. 81) RADAR is used for
(WBCS Preliminary Exam: 2014)
A) submerged submarines
B) radio signals
C) geostationary satellites
D) aeroplanes
Correct Answer: (D) detecting and locating aeroplanes
Q. 83) LCD stands for
(WBCS Preliminary Exam: 2014)
A) Liquid Crystal Display
B) Low Current Display
C) Light Circuit Display
D) None
Correct Answer: (A) Liquid Crystal Display
Q. 84) Basically domestic electric wiring is a
(WBCS Preliminary Exam: 2014)
A) parallel connection
B) series connection
C) combination
D) None
Correct Answer: (A) parallel connection
Q. 85) Heat required to raise body temp by 1 K is
(WBCS Preliminary Exam: 2014)
A) Specific heat
B) Thermal capacity
C) Water equivalent
D) None
Correct Answer: (B) Thermal capacity
Q. 86) Optical fiber works on the
(WBCS Preliminary Exam: 2014)
A) Refraction
B) Total Internal Reflection
C) Scattering
D) Reflection
Correct Answer: (B) Total Internal Reflection
Q. 87) Dyne-sec stands for the unit of :
(WBCS Preliminary Exam: 2013)
A) Force
B) Momentum
C) Energy
D) Power
Correct Answer: (B) Momentum
Q. 88) For same Kinetic energy, momentum is maximum for :
(WBCS Preliminary Exam: 2013)
A) Electron
B) Proton
C) Deuteron
D) Alpha particle
Correct Answer: (D) Alpha particle
Q. 89) Ice cube with air bubble melts in beaker. Water level will:
(WBCS Preliminary Exam: 2013)
A) Remain unchanged
B) Go down
C) Rise
D) First rise then fall
Correct Answer: (A) Remain unchanged
Q. 90) To reduce boiling temperature of water in flask:
(WBCS Preliminary Exam: 2013)
A) Reduce temp
B) Connect evacuating system
C) Less intense heat
D) Connect compressor
Correct Answer: (B) Connect to an evacuating system
Q. 91) Shield instruments from magnetic fields by surrounding with:
(WBCS Preliminary Exam: 2013)
A) Glass shield
B) Rubber shield
C) Brass shield
D) Iron shield
Correct Answer: (D) An iron shield
Q. 92) The first remote sensing satellite from India was :
(WBCS Preliminary Exam: 2012)
A) P6
B) P4
C) IRS 1A
D) CARTOSAT 1
Correct Answer: (C) IRS 1A
Q. 93) Aerial photographs are studied with the help of :
(WBCS Preliminary Exam: 2012)
A) Microscope
B) Stereoscope
C) Parallax bar
D) Theodolite
Correct Answer: (B) Stereoscope
Q. 95) Which of the following is not the unit of length ?
(WBCS Preliminary Exam: 2012)
A) Light year
B) Micron
C) AU
D) Radian
Correct Answer: (D) Radian
Q. 96) Which surface is good absorber of heat ?
(WBCS Preliminary Exam: 2012)
A) White rough
B) Black rough
C) White smooth
D) Black smooth
Correct Answer: (B) Black rough surface
Q. 97) Absolute Zero temperature is where :
(WBCS Preliminary Exam: 2012)
A) Water freezes
B) Molecules at rest
C) Solid state
D) KE and PE equal
Correct Answer: (B) All molecules of water comes to rest
Q. 98) Glass in glycerol invisible because refractive index is:
(WBCS Preliminary Exam: 2012)
A) Greater
B) Lesser
C) Nearly equal
D) Does not depend
Correct Answer: (C) Nearly equal
Q. 99) Gold has higher density than silver due to:
(WBCS Preliminary Exam: 2012)
A) mass number
B) atomic number
C) screening effect
D) Lanthanide contraction
Correct Answer: (D) Lanthanide contraction
Q. 100) When positively charged conductor is earthed:
(WBCS Preliminary Exam: 2012)
A) Electrons conductor to earth
B) Protons conductor to earth
C) Electrons earth to conductor
D) Protons earth to conductor
Correct Answer: (C) Electrons flow from earth to conductor
Q. 101) Which wave is used for telecommunication ?
(WBCS Preliminary Exam: 2012)
A) Infra-red
B) Ultra violet
C) Microwaves
D) X-rays
Correct Answer: (C) Microwaves
Q. 102) An example of a scalar quantity is
(WBCS Preliminary Exam: 2011)
A) Velocity
B) Force
C) Momentum
D) Energy
Correct Answer: (D) Energy
Q. 103) Metal plate with hole is heated. Diameter of hole will:
(WBCS Preliminary Exam: 2011)
A) Increase
B) Decrease
C) Depends on diameter
D) Depends on material
Correct Answer: (A) Increase
Q. 104) Ideal gas volume doubled and temp doubled. Pressure:
(WBCS Preliminary Exam: 2011)
A) Unchanged
B) Doubled
C) One-fourth
D) Four times
Correct Answer: (A) Remains unchanged
Q. 106) Radius of B is half A. Ratio RA/RB of copper wires is:
(WBCS Preliminary Exam: 2011)
A) 1-4
B) 1-8
C) 1-16
D) 1-2
Correct Answer: (C) 1/16
Q. 107) Nuclear reaction in a nuclear reactor is
(WBCS Preliminary Exam: 2011)
A) Fission
B) Fusion
C) Spallation
D) Neutron absorption
Correct Answer: (A) Fission
Q. 108) Dimension of gravitational constant (G) is
(WBCS Preliminary Exam: 2011)
A) cm⁴ sec⁻¹ gm⁻²
B) cm sec⁻³ gm⁻²
C) cm³ sec⁻² gm⁻¹
D) gm cm⁻³ sec⁻²
Correct Answer: (C) cm³ sec⁻² gm⁻¹
Q. 109) Min distance between object and real image in convex lens:
(WBCS Preliminary Exam: 2011)
A) More than 4f
B) Less than 4f
C) Equal to 2f
D) Equal to 4f
Correct Answer: (D) Equal to 4f
Q. 110) Lowest rate of photosynthesis takes place in
(WBCS Preliminary Exam: 2011)
A) Blue light
B) Orange light
C) Green light
D) Red light
Correct Answer: (C) Green light
Q. 111) Rate of radiation of heat highest if surface is
(WBCS Preliminary Exam: 2010)
A) White
B) Smooth
C) Smooth black
D) Rough black
Correct Answer: (D) Rough but black
Q. 112) Min satellites for communication throughout the globe :
(WBCS Preliminary Exam: 2010)
A) 1
B) 2
C) 3
D) 4
Correct Answer: (C) 3
Q. 113) Tube-well will not work if water depth ground is:
(WBCS Preliminary Exam: 2010)
A) 20 ft.
B) 25 ft.
C) 28 ft.
D) 38 ft.
Correct Answer: (D) 38 ft.
Q. 114) Statement check: Newton 1st law, 2nd law, Wiring, TV tube.
(WBCS Preliminary Exam: 2010)
A) Only 1 is correct
B) Only 2 is correct
C) 2 and 4 correct
D) 1 and 4 correct
Correct Answer: (D) Only 1 and 4 are correct
Q. 115) Electrical energy converted into mechanical energy by
(WBCS Preliminary Exam: 2010)
A) Thermostat
B) Motor
C) Dynamo
D) Rectifier
Correct Answer: (B) Motor
Q. 116) Cotton cloth gets wet if one end dipped in water due to
(WBCS Preliminary Exam: 2010)
A) Gravitation
B) Viscosity
C) Elasticity
D) Capillarity
Correct Answer: (D) Capillarity
Q. 118) The weight of an object is
(WBCS Preliminary Exam: 2009)
A) Max at centre
B) Max at infinity
C) Max at surface
D) Same everywhere
Correct Answer: (C) Maximum at the surface of the earth
Q. 119) Water in cavity of ice block at 0°C. Water will:
(WBCS Preliminary Exam: 2009)
A) freeze to ice
B) no change in temp
C) decrease to 0°C
D) freeze if ice is large
Correct Answer: (C) Temperature will decrease to 0°C but not freeze
Q. 120) The walls of a music hall should
(WBCS Preliminary Exam: 2009)
A) Transmit sound
B) Absorb sound
C) Reflect sound
D) Amplify sound
Correct Answer: (B) Absorb sound
Q. 121) EM radiation emitted during radio-active disintegration:
(WBCS Preliminary Exam: 2009)
A) X-rays
B) y-rays
C) Ultraviolet
D) Infra-red
Correct Answer: (B) y-rays
Q. 122) Resistance decreases with rise of temperature in:
(WBCS Preliminary Exam: 2008)
A) Copper
B) Iron
C) Silicon
D) Mercury
Correct Answer: (C) Silicon
Q. 123) Weight of body at the center of the earth is
(WBCS Preliminary Exam: 2008)
A) 0 kg
B) 5 kg
C) 10 kg
D) Infinite
Correct Answer: (A) 0 kg
Q. 124) Movies exemplify the
(WBCS Preliminary Exam: 2008)
A) Phi-phenomenon
B) Autokinetic effect
C) Saccadic movement
D) Purkinje shift
Correct Answer: (A) Phi-phenomenon
Q. 125) The resistance of a 200 V-100 W bulb is
(WBCS Preliminary Exam: 2008)
A) 400 Ω
B) 400 Ω only at 200V
C) 400 Ω not glowing
D) 2 Ω
Correct Answer: (B) 400 Ω only when connected to 200V
Q. 126) Einstein was awarded the Nobel Prize for
(WBCS Preliminary Exam: 2008)
A) Photoelectric equation
B) Special relativity
C) General relativity
D) Brownian motion
Correct Answer: (A) Photoelectric equation
Q. 127) Which one of the following is not an electromagnetic wave?
(WBCS Preliminary Exam: 2008)
A) Radio wave
B) X-ray
C) Visible light
D) Sound wave
Correct Answer: (D) Sound wave
Q. 129) The primary colours of light are
(WBCS Preliminary Exam: 2008)
A) R, G, B, Y
B) Red, blue, green
C) Y, B, R, Grey
D) None
Correct Answer: (B) Red, blue, green
Q. 130) The view finder of a motor car is a
(WBCS Preliminary Exam: 2008)
A) Plane mirror
B) Concave mirror
C) Convex mirror
D) Convex lens
Correct Answer: (C) Convex mirror
Q. 131) Body lifted by hand, what type of work/lever?
(WBCS Preliminary Exam: 2007)
A) First type lever
B) Second type lever
C) Third type lever
D) Simple machine
Correct Answer: (C) Third type lever
Q. 132) Cinema screen white and rough to cause:
(WBCS Preliminary Exam: 2007)
A) Total absorption
B) Total reflection
C) Refraction
D) Scattering
Correct Answer: (D) Scattering (Diffused Reflection)
Q. 133) Temp where 1 cc water mass is 1 gm?
(WBCS Preliminary Exam: 2007)
A) 0°C
B) 100°C
C) 4°C
D) 10°C
Correct Answer: (C) 4°C
Q. 134) Motion of which particle in wire is electric current ?
(WBCS Preliminary Exam: 2007)
A) Electron
B) Positron
C) Neutron
D) Photon
Correct Answer: (A) Electron
Q. 135) Loaded vs empty truck stopping force proves:
(WBCS Preliminary Exam: 2007)
A) Newton 1st law
B) Newton 2nd law
C) Newton 3rd law
D) Gravitational law
Correct Answer: (B) Newton’s second law of motion
Q. 136) Germanium and Silicon are called
(WBCS Preliminary Exam: 2007)
A) Insulators
B) Conductors
C) Metals
D) Semi-conductors
Correct Answer: (d) Semi-conductors
Q. 137) When a body is raised upwards, its weight shall
(WBCS Preliminary Exam: 2007)
A) Increase
B) Remain same
C) Decrease
D) Fluctuate
Correct Answer: (c) Decrease
Q. 138) Two balls at same temp collide. What is conserved?
(WBCS Preliminary Exam: 2006)
A) Temperature
B) Velocity
C) Linear momentum
D) Kinetic energy
Correct Answer: (c) Linear momentum
Q. 139) Kind of energy when watch spring is wound up?
(WBCS Preliminary Exam: 2006)
A) Kinetic energy
B) Potential energy
C) Electrical energy
D) Magnetic energy
Correct Answer: (b) Potential energy
Q. 141) Acceleration due to gravity at higher altitudes
(WBCS Preliminary Exam: 2006)
A) Decreases
B) Increases
C) Remains constant
D) None
Correct Answer: (a) Decreases
Q. 142) Nature of motion of a sewing machine is
(WBCS Preliminary Exam: 2006)
A) Circular
B) Translational
C) Oscillatory
D) Rotational
Correct Answer: (c) Oscillatory motion
Q. 143) 75% decay in 6 hours. Half-life period is
(WBCS Preliminary Exam: 2006)
A) 2 hours
B) 4 hours
C) 4 hours (dup)
D) 3 hours
Correct Answer: (d) 3 hours
Q. 144) Angle of incidence equals critical angle, refraction is
(WBCS Preliminary Exam: 2006)
A) 0°
B) 90°
C) 45°
D) angle of incidence
Correct Answer: (b) 90°
Q. 145) Joining blocks of ice by pressing is called
(WBCS Preliminary Exam: 2006)
A) Regelation
B) Radiation
C) Revelation
D) None
Correct Answer: (a) Regelation
Q. 146) Which one of these is not a measuring instrument?
(WBCS Preliminary Exam: 2005)
A) Barometer
B) Thermometer
C) Picometer
D) Hygrometer
Correct Answer: (c) Picometer (unit)
Q. 147) Both ends of the tube of a Telescope have
(WBCS Preliminary Exam: 2005)
A) convex lens
B) concave lens
C) piano convex lens
D) piano concave lens
Correct Answer: (a) convex lens
Q. 148) Dentists use
(WBCS Preliminary Exam: 2005)
A) Special Mirror
B) Plane Mirror
C) Concave Mirror
D) Convex Mirror
Correct Answer: (c) Concave Mirror
Q. 149) X-ray fails to pass through
(WBCS Preliminary Exam: 2005)
A) Flesh
B) Bone
C) Iron
D) Gold
Correct Answer: (b) Bone
Q. 150) Temp of two bodies equal means
(WBCS Preliminary Exam: 2004)
A) Heat contents same
B) No exchange of heat
C) Heat capacity same
D) Specific heat same
Correct Answer: (B) No exchange of heat in contact
Q. 152) In SHM the kinetic energy
(WBCS Preliminary Exam: 2004)
A) never zero
B) zero twice a period
C) zero in mean
D) always constant
Correct Answer: (B) becomes zero twice in every period
Q. 153) 10g ice (0°C) mixed with 10g water (10°C). Result:
(WBCS Preliminary Exam: 2004)
A) 1°C
B) 5°C
C) 10°C
D) 0°C
Correct Answer: (D) 0°C
Q. 154) Specific resistance of conductor depends on
(WBCS Preliminary Exam: 2004)
A) length
B) width
C) temperature
D) cross-section shape
Correct Answer: (C) temperature
Q. 155) Ship enters sea from river, floats up because
(WBCS Preliminary Exam: 2004)
A) Sea warmer
B) Speed greater
C) River denser
D) Sea water denser
Correct Answer: (d) salt water of the sea is denser
Q. 156) Raindrop falls with uniform velocity
(WBCS Preliminary Exam: 2004)
A) PE constant
B) ME constant
C) ME to atmosphere
D) total energy decays
Correct Answer: (C) mechanical energy transferred to atmosphere
Q. 157) Mass of a body is defined by:
(WBCS Preliminary Exam: 2004)
A) vel/acc
B) force/vel
C) force/acc
D) force/momentum
Correct Answer: (C) applied force / acceleration
Q. 158) Period of rotation of artificial earth satellite
(WBCS Preliminary Exam: 2004)
A) depends on distance
B) proportional to dist
C) inverse to mass
D) 24 hours
Correct Answer: (A) depends on distance from earth surface
Q. 159) The only vector quantity among following:
(WBCS Preliminary Exam: 2004)
A) electric charge
B) electric potential
C) field intensity
D) resistance
Correct Answer: (C) electric field intensity
Q. 160) Induced EMF does not depend on
(WBCS Preliminary Exam: 2004)
A) number of turns
B) pole strength
C) speed
D) resistance
Correct Answer: (D) the resistance of the coil
Q. 161) In p-type semiconductor, main carrier is:
(WBCS Preliminary Exam: 2004)
A) Positive holes
B) positive ions
C) Electrons
D) Negative ions
Correct Answer: (A) Positive holes
Q. 162) Ball dropped, elastic collision. It reaches height:
(WBCS Preliminary Exam: 2004)
A) less than before
B) same as before
C) more than before
D) independent
Correct Answer: (B) same as before
Q. 164) Current on a 100W, 220V bulb is
(WBCS Preliminary Exam: 2004)
A) 2.2 amp.
B) 1.1 amp.
C) 5/11 amp.
D) 22000 amp.
Correct Answer: (C) 5/11 amp.
Q. 165) Red light on green leaf and red flower. Result:
(WBCS Preliminary Exam: 2004)
A) Green leaf, red flower
B) Red leaf, red flower
C) Black leaf, red flower
D) Black leaf, black
Correct Answer: (C) Black leaf and red flower
Q. 166) Magnetic length of bar magnet means
(WBCS Preliminary Exam: 2004)
A) total length
B) dist between poles
C) width
D) dist pole to center
Correct Answer: (B) The distance between its two poles
Q. 167) Rocket trip trip; max energy required to:
(WBCS Preliminary Exam: 2004)
A) rise from earth
B) land on moon
C) rise from moon
D) land on earth
Correct Answer: (A) rise from the earth
Q. 168) Production of shadow proves that
(WBCS Preliminary Exam: 2004)
A) straight line travel
B) EM wave
C) type of particle
D) no diffraction
Correct Answer: (A) light travels approximately in straight lines
Q. 169) Bimetallic strip bends when heated because
(WBCS Preliminary Exam: 2004)
A) different sp heat
B) diff expansion coeff
C) diff temperatures
D) metals become soft
Correct Answer: (B) coefficients of linear expansion are different
Q. 170) Tension of string in vertical rotation max at:
(WBCS Preliminary Exam: 2004)
A) highest position
B) lowest position
C) horizontal
D) always same
Correct Answer: (B) the stone is in the lowest position
Q. 171) Magnifying glass produces a
(WBCS Preliminary Exam: 2004)
A) magnified real
B) virtual same size
C) magnified virtual
D) diminished virtual
Correct Answer: (C) magnified virtual image
Q. 172) Which colour does not match sequence?
(WBCS Preliminary Exam: 2004)
A) Green
B) Red
C) Brown
D) Violet
Correct Answer: (C) Brown (Non-spectral colour)
Q. 173) Viscosity of a liquid
(WBCS Preliminary Exam: 2003)
A) Increases with temp
B) Decreases with temp
C) Independent of temp
D) Decreases with pressure
Correct Answer: (B) Decreases with increase in temperature
Q. 175) Which one of the following is the weakest force?
(WBCS Preliminary Exam: 2003)
A) Gravitational Force
B) Electromagnetic force
C) Nuclear force
D) Electrostatic force
Correct Answer: (A) Gravitational Force
Q. 176) What is increased in the step-down transformer?
(WBCS Preliminary Exam: 2003)
A) Voltage
B) Current
C) Wattage
D) Current density
Correct Answer: (B) Current
Q. 177) When water cools from 7°C to 1°C –
(WBCS Preliminary Exam: 2003)
A) It contracts only
B) It expands only
C) First contracts then expands
D) First expands then contracts
Correct Answer: (C) It first contracts and then expands
Q. 178) Blue colour of the sky is due to
(WBCS Preliminary Exam: 2003)
A) Reflection
B) Refraction
C) Scattering
D) Dispersal
Correct Answer: (C) Scattering
Q. 179) With an ordinary balance we measure
(WBCS Preliminary Exam: 2002)
A) Volume
B) Mass
C) Weight
D) Density
Correct Answer: (B) Mass
Q. 180) A simple microscope was first invented by
(WBCS Preliminary Exam: 2002)
A) Robert Hook
B) Leeuwenhoek
C) Purkinje
D) Robert Brown
Correct Answer: (B) Leeuwenhoek
Q. 181) Why do some automobiles have additional yellow head lights?
(WBCS Preliminary Exam: 2002)
A) Consumes less power
B) No dazzling effect
C) Penetrates fog better
D) Looks more imposing
Correct Answer: (C) Yellow light is able to penetrate fog
Q. 182) One should wear coloured dress in winter because
(WBCS Preliminary Exam: 2001)
A) they look colourful
B) they are cheaper
C) they absorb heat
D) it is easy to wash
Correct Answer: (C) they absorb heat
Q. 183) Iron and wooden ball (same mass) released from height in air. (Neglect drag)
(WBCS Preliminary Exam: 2001)
A) iron hits earlier
B) wooden hits earlier
C) equal probability
D) both reach at same time
Correct Answer: (D) both will reach the ground at the same time
Q. 184) Glass bulb balanced by brass weight. Bell-jar is evacuated:
(WBCS Preliminary Exam: 2001)
A) beam remains horizontal
B) pan with bulb goes up
C) depends on vacuum
D) pan with bulb goes down
Correct Answer: (D) the pan containing the bulb will go down
Q. 185) The emf of a cell does not depend on
(WBCS Preliminary Exam: 2001)
A) the size of the cell
B) material of cathode
C) material of anode
D) electrolyte used
Correct Answer: (A) the size of the cell
Q. 187) A red rose when seen in green light appears
(WBCS Preliminary Exam: 2000)
A) Red
B) Green
C) White
D) Black
Correct Answer: (D) Black in colour
Q. 188) In SI System, number of supplementary units is
(WBCS Preliminary Exam: 2000)
A) 2
B) 3
C) 4
D) Many
Correct Answer: (A) 2 (Radian and Steradian)
Q. 189) A balloon filled with hydrogen bursts at high altitude because:
(WBCS Preliminary Exam: 2000)
A) Pressure inside less
B) Pressure inside more
C) Surface melted
D) Natural phenomenon
Correct Answer: (B) Pressure inside balloon becomes more
Q. 190) X-rays are
(WBCS Preliminary Exam: 2000)
A) Electromagnetic Wave
B) EM wave of short wavelength
C) None of the above
D) EM wave of long wavelength
Correct Answer: (B) Electromagnetic wave of short wavelength
Q. 191) A man presses the earth least when he is
(WBCS Preliminary Exam: 2000)
A) Standing
B) Siting
C) Running
D) Lying flat
Correct Answer: (D) Lying flat
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