Que- In an X-ray tube electrons each of charge e are accelerated through V potential difference allowed to hit a metal target. The wavelength of the X-rays emitted is
a. he/ev
b. he/Vc
c. eV/h
d. impossible to predict
Answer- he/ev
Que- The minimum wavelength of X-rays can further be reduced by
a. Reducing the pressure or cooling the target.
b. Increasing the temperature of the filament.
c. Using a target element of higher atomic number.
d. Increasing the potential difference between the cathode and the target.
Answer- Increasing the potential difference between the cathode and the target.
Que- The characteristic X-rays spectrum is due to
a. The illumination of the target metal by ultra-violet radiation.
b. The bombardment of the target by protons.
c. The bombardment of target by electrons.
d. The absorption of ? radiation by the target metal.
Answer- The bombardment of target by electrons.
Que- The minimum wavelength of X-rays produced by the bombardment of electrons on the screen of a television set where the accelerating potential is 2.0K V will be
a. 6.2 x 10-10m
b. 9.1 x 10-18m
c. 3.11 x 10-10m
d. 4 x 10-10m
Answer- 6.2 x 10-10m
Que- Maximum frequency in the spectrum from X-ray tube is directly proportional to the
a. Number of incident electron i.e. filament current.
b. The kinetic energy of the incident electron i.e. the potential difference through which they are accelerated.
c. The soft target which can easily emit electrons.
d. all of above are correct.
Answer- The kinetic energy of the incident electron i.e. the potential difference through which they are accelerated.
Que- X-rays are diffracted by a crystal but not by a diffraction grating because
a. The ions in a crystal are well arranged.
b. The lines in a diffraction grating cannot reflect X-rays.
c. The penetration power of X-rays is high in a diffraction grating.
d. The wavelengths of X-rays are of the same order of magnitude as the separation between atoms in a crystal
Answer- The wavelengths of X-rays are of the same order of magnitude as the separation between atoms in a crystal
Que- UV radiation can be produced by
a. Heating the filament.
b. Electron excitation in the gas.
c. Ionization of atoms.
d. All the above.
Answer- Electron excitation in the gas.
Que- Wave-like characteristic of electron is demonstrated by
a. Line spectrum of atoms.
b. Production of x-rays.
c. Diffraction by crystalline solids.
d. Photoelectric effect.
Answer- Diffraction by crystalline solids.
Que- Electron cannot exist in the nucleus it is confirmed by observing that
a. It does emit ?-radiation.
b. Its size as compare to proton and neutron is very small.
c. No antiparticle of electron is present.
d. The velocity of electron must be very high according to uncertainty principle.
Answer- The velocity of electron must be very high according to uncertainty principle.
Que- In normal state of energy the incident high energy photons will be
a. Stimulated.
b. Absorbed.
c. Cause X-ray emission.
d. Cause laser production.
Answer- Absorbed.
Que- In laser production the state in which more atoms are in the upper state than in the lower one is called
a. Metal stable state.
b. Normal state.
c. Inverted population.
d. All the above.
Answer- Inverted population.
Que- The metastable state for an atom in laser light is
a. 10-4 sec
b. 10-5 sec
c. 10-3 sec
d. 10-8 sec
Answer- 10-3 sec
Que- In He-Ne laser the lasing action is produced by
a. Ne only.
b. He-Ne both
c. Electrons of He.
d. Electrons Ne.
Answer- Ne only.
Que- Reflecting mirrors in laser is used to
a. Further stimulation
b. Lasing more
c. For producing more energetic lasers.
d. All
Answer- Further stimulation
Que- The velocity of laser light is
a. Less than ordinary light.
b. More than ordinary light.
c. Equal to ordinary light.
d. Different for different colours or frequency.
Answer- Equal to ordinary light.
Que- In nucleus of uranium the number of neutrons will be
a. 92
b. 235
c. 143
d. different for different isotopes
Answer- different for different isotopes
Que- During fusion of hydrogen into helium
a. energy is absorbed
b. energy is released
c. mass is increased due to energy absorption
d. mass is reduced due to energy released
Answer- energy is released
Que- One amu is equal to
a. 1.66 x 10-27kg
b. 166 x 10-15ng
c. 166 x 10-20?g
d. all of above
Answer- all of above
Que- According to which one of following law the density of atom is uniform?
a. J.J.Thomson model
b. Rutherfords model
c. Bohrs model
d. all of above laws contradict the statement
Answer- J.J.Thomson model
Que- For chain reaction to build up the size of the radioactive target should be
a. greater than the critical size
b. less than the critical size
c. equal to the critical size
d. all of above can build up a change reaction
Answer- greater than the critical size
Que- Antimatter consists of
a. antiproton
b. antineutron
c. positron
d. all of above
Answer- all of above
Que- Neutron and proton are commonly known as
a. nucleon
b. meson
c. boson
d. quartz
Answer- nucleon
Que- Half life of radium is 1590 years. In how many years shall the earth loss all its radium due to radioactive decay?
a. 1590x106 years
b. 1590x1012 years
c. 1590x1024 years
d. never
Answer- never
Que- Electrons
a. can exist inside the nucleus
b. cannot exist inside the nucleus
c. can exist both inside and outside the nucleus
d. do not know
Answer- cannot exist inside the nucleus
Que- Radioactivity is a ______ (A) Spontaneous activity (B) Chemical property
a. A & B
b. B & C
c. C & A
d. A B & C
Answer- C & A
Que- Energy liberated when one atom of U-235 undergoes fission reaction is
a. 200MeV
b. 40MeV
c. 30MeV
d. 20MeV
Answer- 200MeV
Que- Transuranic elements have atomic number
a. greater than 72
b. greater than 82
c. greater than 92
d. greater than 102
Answer- greater than 92
Que- Nuclear forces exist between
a. proton-proton
b. proton-neutron
c. neutron-neutron
d. all of the above
Answer- all of the above
Que- Mass defect per nucleon is
a. binding energy of nucleus
b. packing fraction
c. average energy of nucleus
d. all of above are one and same thing
Answer- packing fraction
Que- Tick the correct statement
a. moderators slow down the neutrons
b. moderators bring the neutrons to rest
c. moderators absorb the neutrons
d. moderators reflect the neutrons
Answer- moderators slow down the neutrons
Que- The bombardment of nitrogen with ?-particles will produce
a. neutron
b. Proton
c. electron
d. positron
Answer- Proton
Que- Diameter of an atom is approximately
a. 10-12m
b. 10-11m
c. 10-10m
d. 10-14m
Answer- 10-10m
Que- Average energy required to remove one nucleon from the nucleus is called
a. binding energy per nucleon
b. energy of decay
c. destruction energy
d. all of above
Answer- binding energy per nucleon
Que- Fission chain reaction in a nuclear reactor can be controlled by introducing
a. iron rods
b. graphite rods
c. cadmium rods
d. platinum rods
Answer- cadmium rods
Que- Charge on an electron was determine by
a. Ampere
b. Maxwell
c. Millikan
d. Thomson
Answer- Millikan
Que- Charge on neutron is
a. plus 1.6 x 10-19C
b. zero
c. minus 1.6 x 10-19C
d. no definite charge
Answer- zero
Que- A particle having the mass of an electron and the charge of a proton is called a
a. antiproton
b. positron
c. gamma rays
d. photon
Answer- positron
Que- Mass of neutron is
a. 1.67 x 10-31 kg
b. 1.67 x 10-27 kg
c. 9.1 x 10-31 kg
d. 1.67 x 10-19 kg
Answer- 1.67 x 10-27 kg
Que- Nuclei having the same mass number but different atomic number are
a. Isotopes
b. Isobars
c. Isotones
d. Isomers
Answer- Isobars
Que- A mass spectrograph (spectrometer) sorts out
a. molecules
b. ions
c. elements
d. isotopes
Answer- ions
Que- Sum of the masses of constituent nucleons as compared to the mass of the resultant nucleus is
a. smaller
b. greater than 82
c. same
d. some times smaller some times greater
Answer- greater than 82
Que- The unit of radioactivity curie is equal to
a. 3.74 x 109 disintegration per sec
b. 3.70 x 1010 disintegration per sec
c. 3.55 x 1010 disintegration per sec
d. 3.60 x 1010 disintegration per sec
Answer- 3.70 x 1010 disintegration per sec
Que- During fission process a large amount of
a. heat energy is released
b. nuclear energy is released
c. chemical energy is released
d. light energy is released
Answer- nuclear energy is released
Que- In liquid metal fast breeder reactor the type of uranium used is
a. 92U235
b. 92U238
c. 92U234
d. 92U239
Answer- 92U238
Que- Radioactive materials can be identified by measuring their
a. hardness
b. density
c. mass
d. half life
Answer- half life
Que- If one or more of the neutrons emitted during fission cab be used to build up further fission then the reaction is self sustained and is known as
a. fission reaction
b. fusion reaction
c. chain reaction
d. chemical reaction
Answer- chain reaction
Que- Pair production takes place in the vicinity of a heavy nucleus so that
a. net energy is conserved
b. net charge is conserved
c. net momentum is conserved
d. all of the above
Answer- all of the above
Que- During an encounter with an atom ?-particle knocks out
a. protons
b. electrons
c. neutrons
d. nothing
Answer- electrons
Que- Various types of cancer are treated by
a. cobalt-60
b. strontium-90
c. carbon-14
d. nickel-63
Answer- cobalt-60
Que- Geiger counter is suitable for
a. fast counting
b. extremely fast counting
c. slow counting
d. all situations
Answer- slow counting
Que- Pair production cannot take place in vacuum as ________ is not conserved
a. energy
b. charge
c. mass
d. momentum
Answer- momentum
Que- CFC is used in
a. refrigeration
b. aerosol spray
c. plastic foam industry
d. all of above
Answer- all of above
Que- Average distance covered by ?-particle in air before its ionizing power ceases is called its
a. trajectory
b. range
c. firing level
d. limit
Answer- range
Que- The most useful tracer is
a. Sr-90
b. I-131
c. CA-41
d. C-14
Answer- C-14
Que- Pair production cannot take place in vacuum as
a. mass is not conserved
b. energy is not conserved
c. momentum is not conserved
d. charge is not conserved
Answer- momentum is not conserved
Que- A device for producing high velocity nuclei is
a. cloud chamber
b. linear accelerator
c. a mass spectrograph
d. Wilson cloud chamber
Answer- linear accelerator
Que- The maximum safe limit dose for persons working in nuclear power station are
a. 1 rem per week
b. 5 rem per week
c. 4 rem per week
d. 3 rem per week
Answer- 5 rem per week
Que- The centre of gravity of a sprinter during the race lies
a. Ahead of his feet
b. Behind his feet
c. At the centre of the body
d. To the left side of the body
Answer- Ahead of his feet
Que- Who enunciated the laws of planetary motion?
a. Nicolaus Copernicus
b. Johannes Kepler
c. Isaac Newton
d. Galileo
Answer- Johannes Kepler
Que- The tidal waves on sea is mainly due to
a. Gravitational Effect of Moon on Earth
b. Gravitational Effect of Sun on Earth
c. Gravitational Effect of Earth on Moon
d. None of the above
Answer- Gravitational Effect of Moon on Earth
Que- The time period of a pendulum when taken to the Moon would:
a. Remain the same
b. Decrease
c. Become zero
d. Increase
Answer- Increase
Que- "God Particle" is
a. Neutrino
b. Higgs Boson
c. Meson
d. Positron
Answer- Higgs Boson
Que- In a refrigerator, the cooling system should always be
a. At the top
b. At the bottom
c. At the middle
d. 1.024x10^3
Answer- At the bottom
Que- In a refrigerator what produces the cooling ?
a. The ice which deposits on the freezer
b. The sudden expansion of a compressed gas
c. The evaporation of a volatile liquid
d. None of these
Answer- None of these
Que- Which of the following has the highest entropy?
a. Hydrogen
b. Diamond
c. Liquid nitrogen
d. Mercury
Answer- Hydrogen
Que- Which of these branches of Physics deal with heat and temperature and their relation to energy and work?
a. Geophysics
b. Mechanics
c. Atomic Physics
d. Thermodynamics
Answer- Thermodynamics
Que- The characteristic invalid for heat radiation is that it travels :
a. In a straight line
b. In all directions
c. With the speed of light
d. Heating the medium through which it passes
Answer- With the speed of light
Que- The blue colour of water in the sea is due to
a. Absorption of other colours except blue by water molecules
b. Scattering of blue light by water molecules
c. Reflection of blue light by impurities in sea water
d. Reflection of blue sky by sea water
Answer- Absorption of other colours except blue by water molecules
Que- The bending of light when it passes around a corner or a slit is due to ________
a. Reflection
b. Refraction
c. Diffraction
d. Total internal reflection
Answer- Diffraction
Que- The colour of the ocean appears to be blue because the sunlight falling on it is
a. Reflected
b. Refracted
c. Diffracted
d. Scattered
Answer- Scattered
Que- Which of the following statements is true when we see ''rainbow' ?
a. We face sun and raindrops
b. The Sun remains behind us and we face raindrops
c. In light rainfall, we face Sun
d. The sky remains clear and the sun is at lower position in the sky
Answer- The Sun remains behind us and we face raindrops
Que- Danger signals are generally red as red light
a. Is least bright
b. Undergoes least deviation
c. Has lowest velocity
d. Gives comfort to eye
Answer- Undergoes least deviation
Que- The bats can fly in the dark because
a. They can see the objects in darkness
b. They have weak legs and are likely to be attacked by predators
c. They generate flashes of light
d. They generate ultrasonic sound waves
Answer- They generate ultrasonic sound waves
Que- The device used for locating submerged objects under sea is.
a. Sonar
b. Radar
c. Laser
d. Maser
Answer- Sonar
Que- The sounds having a frequency of 20 Hertz to 20,000 Hertz are known as
a. Audible sounds
b. Ultrasonics
c. Infrasonics
d. Megasonics
Answer- Audible sounds
Que- In mirrors the back surface is coated with a thin layer of :
a. Mercury
b. Silver
c. Red oxide
d. Silver nitrate
Answer- Silver
Que- A light ray travelling from denser to rarer medium at an angle of incidence more than critical angle of concerned media pair suffers.
a. Reflection
b. Refraction
c. Diffraction
d. Total internal reflection
Answer- Total internal reflection
Que- When a body falls from an aeroplane, there is increase in its
a. Kinetic energy
b. Mass
c. Acceleration
d. Potential energy
Answer- Acceleration
Que- Which of the following never occurs singly in nature?
a. Inertia
b. Momentum
c. Force
d. Velocity
Answer- Force
Que- The moment of inertia of a body does not depend upon
a. The mass of the body
b. The mass distribution in the body
c. The angular speed of the body
d. The axis of rotation of the body
Answer- The angular speed of the body
Que- Newton's first law of motion gives the concept of
a. Energy
b. Work
c. Momentum
d. Inertia
Answer- Inertia
Que- For every action, there is an equal and opposite reaction, is Newton's
a. First law
b. Second law
c. Third law
d. Fourth law
Answer- Third law
Que- A small gap is left at the joints of rails in a railway track to
a. Avoid the tracks being distorted due to seasonal temperature variation
b. Avoid the heating of tracks to high temperature
c. Control the speed of train
d. Keep the rails equidistant
Answer- Avoid the tracks being distorted due to seasonal temperature variation
Que- Pipelines in cold countries often burst in winter, because
a. Water freezes and expands in its volume
b. Temperature of ice is less than that of water
c. Pipelines contract in their volume
d. Pipelines expand due to freezing
Answer- Water freezes and expands in its volume
Que- In severe winter, in cold countries water pipes burst because
a. Water expands on freezing
b. Contraction of water pipes
c. High atmospheric pressure
d. Combined effect of all the above three
Answer- Water expands on freezing
Que- Railway tracks are banked on curves so that
a. Necessary centrifugal force may be obtained from the horizontal component of the weight of the train
b. No frictional force may be produced between the tracks and the wheels of the train
c. Necessary centripetal force may be obtained from the horizontal component of the weight of the train
d. The train may not fall down inwards
Answer- Necessary centripetal force may be obtained from the horizontal component of the weight of the train
Que- The density of the liquid when heated
a. Decreases
b. Increases
c. Does not change
d. May increase of decrease depending on pressure
Answer- Decreases
Que- The modulus of elasticity for mild steel is approximately equal to
a. 210 kN/mm2
b. 100 kN/mm2
c. 80 kN/mm2
d. 10 kN/mm2
Answer- 210 kN/mm2
Que- The Hooke's law is valid for
a. Only proportional region of the stress strain curve
b. Entire stress strain curve
c. Entire elastic region of the stress strain curve
d. Elastic as well as plastic region of the stress strain curve
Answer- Only proportional region of the stress strain curve
Que- Gas thermometers are more sensitive than the liquid thermometers because the gases
a. Have large coefficient of expansion
b. Are lighter
c. Have low specific heat
d. Have high,specific heat
Answer- Have large coefficient of expansion
Que- What happens to a liquid, when the vapour pressure equals the atmospheric pressure?
a. The liquid cools
b. The liquid boils
c. No change
d. The liquid evaporates
Answer- The liquid boils
Que- If the temperature of a place increases suddenly, the relative humidity
a. Increases
b. Decreases
c. Remains constant
d. Fluctuates
Answer- Decreases
Que- In beta decay what is emitted?
a. Electron
b. Proton
c. Neutron
d. All of the above
Answer- Electron
Que- Which one of the following ray has minimum wavelength?
a. Gamma ray
b. Cosmic ray
c. Utraviolet ray
d. X-rays
Answer- Gamma ray
Que- Nuclear Fission is caused by the impact of
a. Electron
b. Neutron
c. Proton
d. Deutron
Answer- Neutron
Que- Radiocarbon dating technique is used to estimate the age of
a. Fossils
b. Rocks
c. Monuments
d. Soil
Answer- Fossils
Que- Which of the following branch of Physics deal with study of Atomic Nuclei?
a. Nuclear Physics
b. Bio Physics
c. Atomic Physics
d. None of the above
Answer- Nuclear Physics
Que- Gamma rays can cause
a. Gene mutation
b. Sneezing
c. Burning
d. Fever
Answer- Gene mutation
Que- Green house effect is the heating up of the Earth's atmosphere which is due to
a. The ultraviolet rays
b. G-rays
c. The infra-red rays
d. X-rays
Answer- The infra-red rays
Que- Visible light has a higher frequency than
a. Radio waves
b. X rays
c. Ultra violet
d. All the above
Answer- Radio waves