Description : Which one of the following waves requires a material medium for their propagation? a) Light waves b) X– rays c) -rays d) Sound waves
Last Answer : d) Sound waves
Description : Pair production can be studied with a) Ultraviolet rays b) X-rays c) Microwaves d) -rays
Last Answer : d) -rays
Description : By the transition of inner shell electrons in heavy atoms, high energy photons are emitted which are a) gamma rays b) X-rays c) radio waves d) photon rays
Last Answer : b) X-rays
Description : All of the following are electromagnetic radiations except-----? A. Red light B. Sound waves (Answer) C. X-Rays D. Photon
Last Answer : B. Sound waves (Answer)
Description : Which one of the following phenomena can be studied with -rays a) Photoelectric effect b) Compton effect c) Pair production d) All of the above
Last Answer : a) Photoelectric effect
Description : Whichofthe followingterms describesthe reason thatlightisrefractedat different angles? a. Photon energy changes with wavelength b. Light is refracted as a function of surface smoothness c. The angle is determined partly by a and b d. The angle is determined by the index of the materials
Last Answer : d. The angle is determined by the index of the materials
Description : The emission in which the atom emits a photon of energy hf = E2 – E1 , in any arbitrary direction is a) Spontaneous emission b) stimulated emission c) induced emission d) both a & c
Last Answer : d) both a & c
Description : The incident photon absorbed by an atom in the ground state E1, thereby leaving the atom in the excited state E2 , is a) spontaneous absorption b) stimulated absorption c) induced absorption d) both b & c
Last Answer : d) both b & c
Description : Rest mass of the photon is a) Infinite b) Zero c) Very small d) 1.67 10-27 Kg
Last Answer : b) Zero
Description : If energy of incident photon is greater than the rest mass energy of electron positron pair, the surplus energy is shared by the pair as, a) Potential energy b) Thermal energy c) Electronic energy d) Kinetic energy
Last Answer : d) Kinetic energy
Description : The phenomena of pair production occurs only when the energy of incident photon is least equal a) 10.2 MeV b) 1.02 MeV c) 1.02 eV d) 0.102 MeV
Last Answer : b) 1.02 MeV
Description : The radiations emitted by human body lies in a) Infrared region b) Ultraviolet region c) Visible region d) None of the above
Last Answer : a) Infrared region
Description : The waves used for sending signals to the satellite from ground station are _____. A. Ultraviolet rays B. X-rays C. Sound waves D. Micro waves
Last Answer : ANSWER: D
Description : Coolis tube is used to produce – (1) Radio waves (2) Micro waves (3) X-rays (4) Gama rays
Last Answer : (3) X-rays Explanation: X-rays are part of the electromagnetic spectrum, an ionizing radiation with wavelengths shorter than ultraviolet light. X-ray tubes evolved from experimental Crookes tubes ... X-rays created the field of radiography, the imaging of opaque objects with penetrating radiation.
Description : Coolis tube is used to produce (1) Radio waves (2) Micro waves (3) X-rays (4) Gama rays
Last Answer : X-rays
Description : Ozone layer in the outer atmosphere helps us in – (1) reflecting radio waves and makes radio communication possible (2) regulating he temperature of atmosphere (3) absorbing cosmic ray particles (4) absorbing U-V radiations
Last Answer : (4) absorbing U-V radiations Explanation: The ozone layer is a layer in Earth's atmosphere containing relatively high concentrations of ozone (03) which absorbs 97- 99% of the Sun's medium-frequency ultraviolet light.
Description : Ozone layer in the outer atmosphere helps us in (1) reflecting radio waves and makes radio communication possible (2) regulating the temperature of atmosphere (3) absorbing cosmic ray particles (4) absorbing U-V radiations
Last Answer : absorbing U-V radiations
Description : Electric power a. V×I b. W/t c. V 2 /I d. E2 /t
Last Answer : . V×I
Description : X-rays that are emitted in all directions and with a continuous range of frequencies are known as a) characteristic X-rays b) continuous X-rays c) scattered X-rays d) stimulated X-rays.
Last Answer : b) continuous X-rays
Description : The reverse process of photo-electric effect is called: a) Annihilation of matter b) Compton effect c) Pair production d) X-rays
Last Answer : d) X-rays
Description : X-rays were discovered by: a) Roentgen b) Becquerel c) Marie Curie d) Van Lave
Last Answer : a) Roentgen
Description : The X-rays emitted in inner shell transitions are called _____ as their energy depends upon the type of target material. a) gamma rays b) special X-rays c) Characteristic X-rays d) continuous X-rays
Last Answer : c) Characteristic X-rays
Description : In human flesh, the three light elements which predominate, and allow greater amount of incident X-rays to pass through them are a) oxygen, nitrogen , hydrogen b) oxygen, hydrogen, helium c) oxygen, hydrogen, carbon d) carbon, nitrogen, oxygen
Last Answer : c) oxygen, hydrogen, carbon
Description : X-rays can penetrate several ____ into a solid matter. a) millimeters b) meters c) centimeters d) kilometers
Last Answer : c) centimeters
Description : For the production of X-rays, the electrons which strike with the target are a) slow moving b) fast moving c) vibrational electrons d) free electrons
Last Answer : b) fast moving
Description : The practical application of electrostatic is: (a) Photocopier (b) X-rays machines (c) Laser (d) All of above 42. The electric field lines emerge from the charges in: (a) Three dimensions (b) Two dimensions (c) One dimension (d) All of above
Last Answer : (a) Photocopier
Description : Why are we able to hear shortwave broadcasts better than long wave broadcasts? (a) Short wave broadcasts are made by nearby radio stations (b) Short waves are unaffected by atmospheric ... convention, short waves are meant for long distances whereas long waves are reserved for short distances
Last Answer : Ans:(c) Direction: In the following question, a statement of Assertion (A) is given followed by corresponding Reason (R), just below it. Read the statements carefully and mark the correct answer: (a) If both A and ... true but R is not the correct explanation of A. (c) If A is true but R is false
Description : Why are we able to hear short wave broadcasts better than long wave broadcasts? (1) Short waves are more energetic than long waves (2) Short waves are unaffected by atmospheric disturbances ... convention, short waves are meant for long distances, whereas long waves are reserved for short distances
Last Answer : (1) Short waves are more energetic than long waves Explanation: Shortwave radio is used for broadcasting of voice and music, and longdistance communication to ships and aircraft, or to remote areas ... wired communication or other radio services and that's why it is more energetic than long waves.
Description : Why are we able to hear short wave broadcasts better than long wave broadcasts ? (1) Short waves are more energetic than long waves. (2) Short waves are unaffected by atmospheric ... convention, short waves are meant for long distances, whereas long waves are reserved for short distances.
Last Answer : Short waves are more energetic than long waves.
Description : Current gain of a transistor which has collector current of 10 mA and a base current of 40 micro Ampere is: (a) 25 (b) 250 (c) 2500 (d) 25000
Last Answer : b) 250
Description : A photodiode can switch its current ON or OFF in (a) nano second (b) milli second (c) micro second (d) centi second
Last Answer : (a) nano second
Description : When current of one ampere is flowing across any cross-section of wire in one second, then the quantity of charge is said to be: (a) One coulomb (b) Three coulomb (c) One micro-coulomb (d) None of above
Last Answer : (a) One coulomb
Description : The alpha particles are A)High`-` energy electrons B)Positively charged hydrogen ions C) High`-` energy `X-` rays radiations D)Double positively charg
Last Answer : The alpha particles are A)High`-` energy electrons B)Positively charged hydrogen ions C) ... ray radiations D. double positively charged helium nuclei
Description : Ozone saves the biosphere by absorbing high energy radiations called - (1) Infra-red (2) Gamma rays (3) Ultraviolet rays (UV) (4) X-rays
Last Answer : (3) Ultraviolet rays (UV) Explanation: The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet (UV) radiation. It absorbs 97 to 99 ... 200 nm to 315 nm wavelength), which otherwise would potentially damage exposed life forms near the surface.
Description : Which, of the following radiations has the least wavelength? (1) X-rays (2) a-rays (3) g-rays (4) b-rays
Last Answer : (3) g-rays Explanation: X-rays - smaller than 10 nano metre gamma- rays - 0.0005 to 0.1 nano metre alpha-rays - 125 nano metre
Description : What are the electromagnetic radiations of wavelengths less than 300 angstroms? A. X-rays B. Ultraviolet rays C. Infrared D. Microwaves
Last Answer : A. X-rays
Description : Which of the following radiations is the least penetrating? (A) α-rays (B) β-rays (C) γ-rays (D) X-rays
Last Answer : (A) α-rays
Description : Ozone saves the biosphere by absorbing high energy radiations called _____ . (1) Infra-red (IR) (2) Gamma rays (3) Ultraviolet rays (UV) (4) X–rays
Last Answer : Ultraviolet rays (UV)
Description : Which, of the following radiations has the least wavelength ? (1) X-rays (2) a-rays (3) g-rays (4) b-rays
Last Answer : g-rays
Description : ___________ remain undeflected in a magnetic field a) β particles b) α particles c) γ rays d) Proton beams
Last Answer : c) γ rays
Description : .Diffractionof electromagneticwaves a. is caused by reflections from the ground b. arises only with spherical wavefronts c. will occur when the waves pass through a large slot d.may occuraroundthe edge of asharpobstacle
Last Answer : d.may occuraroundthe edge of asharpobstacle
Description : The absorption ofradiowaves bythe atmosphere depends on a. their frequency b. their distance from the transmitter c. the polarization of the waves d. the polarization of the atmosphere
Last Answer : a. their frequency
Description : .In electromagneticwaves,polarization a. is caused by reflection b.isdue to the transversenature ofthewaves c. results from the longitudinal nature of the waves d. is always vertical in an isotropic medium
Last Answer : b.isdue to the transversenature ofthewaves
Description : FrequenciesintheUHFrange normallypropagate bymeans of a. ground waves b. sky waves c. surface waves d.spacewaves
Last Answer : d.spacewaves
Description : The concept that particles can behave like waves was given by a) Compton b) De-Broglie c) G.P. Thomson d) Germer
Last Answer : b) De-Broglie
Description : Light waves can cause photoelectric emission in a) Metals b) Alkali metals c) Insulators d) None of the above
Last Answer : c) Insulators
Description : de Broglie’s relation for matter waves was experimentally verified by: a) Davisson b) Germer c) G.P. Thomson d) All the these
Last Answer : c) G.P. Thomson