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NEET UG CHEMISTRY MCQ: STRUCTURE OF ATOM
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Medium
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Analyzing
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Assertion (A): Red light of any brightness may shine on a piece of potassium-metal but no photoelectrons are ejected but as soon as even a very weak yellow light shines on the potassium-metal, the photoelectric effect is observed.
Reason (R): The number of electrons ejected does depend upon the brightness of light and not on the kinetic energy of the ejected electrons.
Reason (R): The number of electrons ejected does depend upon the brightness of light and not on the kinetic energy of the ejected electrons.
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Correct option: A
Both Assertion and Reason are correct; Reason is the correct explanation of Assertion
Option A (Both Assertion and Reason are correct; Reason is the correct explanation of Assertion) is correct because the photoelectric effect depends on the frequency of light, not brightness, and the number of ejected electrons depends on brightness.
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Which of the following pairs have identical values of e/m?
The correct de Broglie relationship is:
Assertion: Unlike sound waves, electromagnetic waves do not require medium and can move in vacuum.
Reason: The oscillating electric and magnetic fields produced by oscillating charged particles are parallel to each other and both are perpendicular to the direction of propagation of the wave. S-I: The orbital has maximum electron density along the y axis and its nodal plane is xz plane.
S-II : For a given atom, for all values of , the -orbitals have the same shape, but the overall size decreases as '' increases. S-I: Elements like and were discovered when their minerals were analysed by spectroscopic methods.
S-II: The element helium was discovered in the sun by spectroscopic method. In which one of the following, the number of protons is greater than number of neutrons but number of protons is less than the number of electrons?
Reason: The oscillating electric and magnetic fields produced by oscillating charged particles are parallel to each other and both are perpendicular to the direction of propagation of the wave. S-I: The orbital has maximum electron density along the y axis and its nodal plane is xz plane.
S-II : For a given atom, for all values of , the -orbitals have the same shape, but the overall size decreases as '' increases. S-I: Elements like and were discovered when their minerals were analysed by spectroscopic methods.
S-II: The element helium was discovered in the sun by spectroscopic method. In which one of the following, the number of protons is greater than number of neutrons but number of protons is less than the number of electrons?