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question_answer1) Assertion : The energy and momentum (p) of a photon are related by \[p=E/c\]. Reason : The photon behaves like a particle. [AIIMS 2005]
question_answer2) Assertion : Photoelectric effect demonstrates the wave nature of light. Reason : The number of photoelectrons is proportional to the frequency of light.[AIIMS 2004]
question_answer3) Assertion : When the speed of an electron increases its specific charge decreases. Reason : Specific charge is the ratio of the charge to mass. [AIIMS 2001]
question_answer4) Assertion : X-ray travel with the speed of light. Reason : X-rays are electromagnetic rays. [AIIMS 2001]
question_answer5) Assertion : Mass of moving photon varies inversely as the wavelength. Reason : Energy of the particle \[=\text{ Mass }\times \text{ (Speed of light}{{\text{)}}^{\text{2}}}\] [AIIMS 2000]
question_answer6) Assertion : Kinetic energy of photo electrons emitted by a photosensitive surface depends upon the intensity of incident photon. Reason : The ejection of electrons from metallic surface is possible with frequency of incident photon below the threshold frequency. [AIIMS 1999]
question_answer7) Assertion : Separation of isotope is possible because of the difference in electron numbers of isotope. Reason : Isotope of an element can be separated by using a mass spectrometer. [AIIMS 1999]
question_answer8) Assertion : The specific charge of positive rays is not constant. Reason : The mass of ions varies with speed. [AIIMS 1999]
question_answer9) Assertion : Photosensitivity of a metal is high if its work function is small. Reason : Work function \[=h{{f}_{0}}\] where \[{{f}_{0}}\] is the threshold frequency. [AIIMS 1997]
question_answer10) Assertion : The de-Broglie wavelength of a molecule varies inversely as the square root of temperature. Reason : The root mean square velocity of the molecule depends on the temperature. [AIIMS 1997]
question_answer11) Assertion : An electron is not deflected on passing through certain region of space. This observation confirms that there is no magnetic field in that region. Reason : The deflection of electron depends on angle between velocity of electron and direction of magnetic field.
question_answer12) Assertion : Electric conduction in gases is possible at normal pressure. Reason : The electric conduction in gases depends only upon the potential difference between the electrodes.
question_answer13) Assertion : Light is produced in gases in the process of electric discharge through them at high pressure. Reason : At high pressure electrons of gaseous atoms collide and reach and excited state.
question_answer14) Assertion : If different gases are filled turn by turn at the same pressure in the discharge tube the discharge in them takes place at the same potential. Reason : The discharge depends only on the pressure of discharge tube and not on the ionisation potential of gas.
question_answer15) Assertion : An electric field is preferred in comparison to magnetic field for detecting the electron beam in a television picture tube. Reason : Electric field require low voltage.
question_answer16) Assertion : The specific charge for positive rays is a characteristic constant. Reason : The specific charge depends on charge and mass of positive ions present in positive rays.
question_answer17) Assertion : In Millikan's experiment for the determination of charge on an electron, oil drops of any size can be used. Reason : Millikan's experiment determine the charge on electron, by simply measuring the terminal velocity.
question_answer18) Assertion : In the process of photoelectric emission, all the emitted photoelectrons have the same kinetic energy. Reason : The photon transfers its whole energy to the electron of the atom in photoelectric effect.
question_answer19) Assertion : In photoelectric effect, on increasing the intensity of light, both the number of electrons emitted and kinetic energy of each of them get increased but photoelectric current remains unchanged. Reason : The photoelectric current depends only on wavelength of light.
question_answer20) Assertion : Though light of a single frequency (monochromatic) is incident on a metal, the energies of emitted photoelectrons are different. Reason : The energy of electrons emitted from inside the metal surface is lost in collision with the other atoms in the metal.
question_answer21) Assertion : The threshold frequency of photoelectric effect supports the particle nature of sunlight. Reason : If frequency of incident light is less than the threshold frequency, electrons are not emitted from metal surface.
question_answer22) Assertion : In photoemissive cell inert gas is used. Reason : Inert gas in the photoemissive cell gives greater current.
question_answer23) Assertion : X-rays cannot be diffracted by means of grating. Reason : X-rays does not obey Bragg's law.
question_answer24) Assertion : X-rays can penetrate through the flesh but not through the bones. Reason : The penetrating power of X-rays depends on voltage.
question_answer25) Assertion : Intensity of X-rays can be controlled by adjusting the filament current and voltage. Reason : The intensity of X-rays does not depend on number of X-ray photons emitted per second from the target.
question_answer26) Assertion : Anode of Coolidge tube gets heated up at time of emission of X-rays. Reason : The anode of Coolidge tube is made of a material of high melting point.
question_answer27) Assertion : Penetrating power of X-rays increases with the increasing the wavelength. Reason : The penetrating power of X-rays increases with the frequency of X-rays.
question_answer28) Assertion : X-rays are used for studying the structure of crystals. Reason : The distance between the atoms of crystals is of the order of wavelength of X-rays.
question_answer29) Assertion : The phenomenon of X-ray production is basically inverse of photoelectric effect. Reason : X-rays are electromagnetic waves.
question_answer30) Assertion : Soft and hard X-rays differ in frequency as well as velocity. Reason : The penetrating power of hard X-rays is more than the penetrating power of soft X-rays.
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