12. Atoms
рдЗрд╕ рдкреЗрдЬ рдкрд░ рдЖрдкрдХреЛ 12. Atoms рдХреЗ рд╕рднреА рдорд╣рддреНрд╡рдкреВрд░реНрдг рдмрд╣реБрд╡рд┐рдХрд▓реНрдкреАрдп рдкреНрд░рд╢реНрди (MCQ), рдкрд░реАрдХреНрд╖рд╛ рдЙрдкрдпреЛрдЧреА рдиреЛрдЯреНрд╕ рдФрд░ рдСрдирд▓рд╛рдЗрди рдХреНрд╡рд┐рдЬрд╝ рдорд┐рд▓реЗрдВрдЧреЗред рдЕрдкрдиреЗ рдЬреНрдЮрд╛рди рдХрд╛ рдкрд░реАрдХреНрд╖рдг рдХрд░рдиреЗ рдФрд░ рдмреЛрд░реНрдб/рдкреНрд░рддрд┐рдпреЛрдЧреА рдкрд░реАрдХреНрд╖рд╛ рдореЗрдВ рд╢рдд-рдкреНрд░рддрд┐рд╢рдд рдЕрдВрдХ рдкреНрд░рд╛рдкреНрдд рдХрд░рдиреЗ рдХреЗ рд▓рд┐рдП рдиреАрдЪреЗ рджрд┐рдП рдЧрдП рдореЙрдХ рдЯреЗрд╕реНрдЯ рдореЗрдВ рдЕрд╡рд╢реНрдп рднрд╛рдЧ рд▓реЗрдВред
ЁЯСЙ рдЕрдзреНрдпрд╛рдп рдХрд╛ рд╕рд╛рд░рд╛рдВрд╢ (Summary)
Dear students, in this chapter, we will deeply study 1 extremely fascinating and highly fundamental branch of physics that literally takes us inside the microscopic building blocks of the entire universe: 'Atoms'. In the previous chapter, we scientifically learned about the dual nature of radiation and matter. Now, we will logically shrink our focus to the tiniest possible scale to understand what exactly makes up all the solid, liquid, and gaseous materials around us. For 1000s of years, brilliant philosophers strongly believed that matter is made of indivisible tiny particles. But it was only in the late 19th and early 20th century that modern scientists practically proved the existence of subatomic particles like electrons and completely revealed the hidden internal structure of the atom.
Instead of just cramming complex mathematical equations in closed books, if we logically connect physics with our modern daily life, it feels extremely magical. Have you ever thought deeply about how the bright, colorful neon sign boards glowing at night in massive city markets exactly work? Or how the highly precise lasers used in modern hospitals for delicate eye surgeries successfully produce such 1 intense and focused beam of light? This is no magic trick, but it is 100 percent the scientific marvel of atomic energy levels and electron transitions. When we pass high voltage electricity through 1 glass tube completely filled with neon gas, the tiny electrons inside the neon atoms actively absorb energy and jump to 1 higher energy state. When they quickly return to their original normal state, they magically release that exact same energy in the form of beautiful colored light. Every single chemical element has its own 100 percent unique atomic fingerprint or emission spectrum.
From the strict perspective of the upcoming NCERT and RBSE board exams, this specific chapter of physics is highly scoring and extremely important for your 100 percent success. In the board exams, not only direct theoretical questions are asked from this chapter, but excellent analytical, numerical, and derivation-based questions on the Bohr model, energy level diagrams, and the hydrogen spectrum definitely appear in the final exam paper every single year without fail. In this highly exciting journey, we will 1st study the historical alpha-particle scattering experiment heavily conducted by Ernest Rutherford. We will scientifically learn how he shockingly discovered that almost 100 percent of the massive weight of 1 atom is strictly concentrated in 1 extremely tiny, dense, and positively charged central core called the nucleus, while the tiny electrons revolve around it in massive empty spaces.
Moving 1 little further in the chapter, we will logically analyze the massive limitations of Rutherford's model. According to classical physics, his revolving electrons should continuously lose energy and instantly collapse into the nucleus, totally destroying the atom. To perfectly solve this massive problem, Niels Bohr brilliantly introduced his highly revolutionary quantum model of the hydrogen atom in exactly 1913. We will deeply study Bohr's 3 magical postulates, which strictly state that electrons can only revolve in specific discrete orbits without losing even 1 single drop of energy. We will mathematically calculate the exact radius of these orbits and the total energy of the electrons. After this, we will deeply understand the fascinating Hydrogen Spectrum, logically learning about the exact sequence of the Lyman, Balmer, Paschen, Brackett, and Pfund spectral series.
To perfectly ensure your excellent and 100 percent strong preparation, we have meticulously selected and prepared completely accurate, high-level, and highly exam-useful objective questions (MCQs) from all these complex topics. By continuously practicing again and again, you will surely learn critical time management and massively increase your speed of solving complex numerical questions without making even 1 single mistake.
Feature: This is 1 3-Level based unique quiz. To unlock the next level (Level 2 and 3), students must score at least 70% in the current level, making their board exam preparation 100% strong.
рдорд╣рддреНрд╡рдкреВрд░реНрдг рдкреНрд░рд╢реНрди (Important Questions)
PDF рдбрд╛рдЙрдирд▓реЛрдб рдХрд░реЗрдВрдЕрдзреНрдпрд╛рдп рдХреЗ рд╕рднреА рдкреНрд░рд╢реНрди (Revision Notes)
*рдиреЛрдЯ: рдпрд╣ рд╕реЗрдХреНрд╢рди рд░рд┐рд╡реАрдЬрди рдХреЗ рд▓рд┐рдП рд╣реИред рдЕрдкрдирд╛ рдЬреНрдЮрд╛рди рдкрд░рдЦрдиреЗ рдХреЗ рд▓рд┐рдП рдКрдкрд░ рджрд┐рдП рдЧрдП рдХреНрд╡рд┐рдЬрд╝ рдореЗрдВ рднрд╛рдЧ рд▓реЗрдВред
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Who discovered the Nucleus?
A) Thomson | B) Rutherford | C) Bohr | D) Chadwick -
Particles bombarded in Rutherford's experiment?
A) Electron | B) Proton | C) Alpha (╬▒) | D) Neutron -
Most part of atom is?
A) Solid | B) Empty | C) Negative | D) Liquid -
Angular momentum L in Bohr model:
A) nh/2╧А | B) h/2╧А | C) n┬▓h/2╧А | D) h/╧А -
First Bohr radius of Hydrogen?
A) 0.53 ├Е | B) 1.06 ├Е | C) 0.26 ├Е | D) 5.3 ├Е -
Who gave Plum Pudding model?
A) Rutherford | B) Thomson | C) Bohr | D) Dalton -
Which series is in visible region?
A) Lyman | B) Balmer | C) Paschen | D) Brackett -
Size of nucleus approx:
A) 10тБ╗┬╣тБ░ m | B) 10тБ╗┬╣тБ╡ m | C) 10тБ╗тБ╕ m | D) 10тБ╗┬╣┬▓ m -
When electron jumps from high to low orbit, energy is:
A) Absorbed | B) Emitted | C) No change | D) Destroyed -
Energy in ground state (n=1) of H-atom?
A) -13.6 eV | B) -3.4 eV | C) +13.6 eV | D) 0 -
Unit of Rydberg constant (R):
A) m | B) mтБ╗┬╣ | C) Joule | D) Second -
Particles in nucleus:
A) Only proton | B) Proton & Neutron | C) Proton & Electron | D) Only neutron -
Bohr's 2nd postulate is quantization of:
A) Charge | B) Angular momentum | C) Energy | D) Mass -
Atoms are electrically:
A) Positive | B) Negative | C) Neutral | D) Polar -
Lyman series region:
A) Visible | B) Infrared | C) UV | D) X-ray -
Scattering angle if Impact Parameter is zero:
A) 0┬░ | B) 90┬░ | C) 180┬░ | D) 45┬░ -
Energy vs orbit number (n) in Bohr model:
A) E тИЭ n | B) E тИЭ n┬▓ | C) E тИЭ 1/n┬▓ | D) E тИЭ 1/n -
Velocity (v) vs n in H-atom:
A) n | B) 1/n | C) n┬▓ | D) 1/n┬▓ -
Excitation Potential is min potential to:
A) Remove e- | B) Send e- to high orbit | C) Break nucleus | D) None -
Paschen series region:
A) UV | B) Visible | C) Infrared | D) X-ray -
Major drawback of Rutherford model:
A) Atomic stability | B) Nucleus discovery | C) Electron existence | D) Neutrality -
Ionization Energy of H-atom:
A) 13.6 eV | B) 3.4 eV | C) 1.51 eV | D) 0.85 eV -
Energy in n=2 for H-atom?
A) -13.6 eV | B) -3.4 eV | C) -1.51 eV | D) -6.8 eV -
Bohr model valid for:
A) All | B) Hydrogen-like (1 e-) | C) Heavy | D) Gases -
Distance of closest approach depends on:
A) ╬▒-energy | B) Ze charge | C) Both | D) None -
Centripetal force for electron rotation from:
A) Gravity | B) Coulomb force | C) Magnetic | D) None -
Highest wavelength series:
A) Lyman | B) Balmer | C) Paschen | D) Pfund -
Total energy of electron in atom is:
A) Always positive | B) Always negative | C) Zero | D) Infinite -
rтВЩ and aтВА relation:
A) rтВЩ = aтВА n┬▓ | B) rтВЩ = aтВА/n┬▓ | C) rтВЩ = aтВА n | D) rтВЩ = aтВА/n -
KE and Total Energy (E) relation in Bohr:
A) K = E | B) K = -E | C) K = 2E | D) K = -E/2 -
r1 = 0.53 ├Е. r3 is?
A) 1.59 ├Е | B) 4.77 ├Е | C) 0.17 ├Е | D) 2.12 ├Е -
e- n=2 to n=1. Photon energy?
A) 13.6 eV | B) 10.2 eV | C) 3.4 eV | D) 1.89 eV -
First Bohr radius of Li++ (Z=3) vs H-atom:
A) 3 times | B) 1/3 times | C) 9 times | D) Equal -
Shortest wavelength of Balmer series:
A) R | B) 1/R | C) 4/R | D) 9/R -
PE (U) and Total Energy (E) relation:
A) U = E | B) U = 2E | C) U = E/2 | D) U = -E -
Angular frequency (╧Й) vs n:
A) 1/n┬▓ | B) 1/n┬│ | C) n | D) n┬▓ -
As Z increases, Bohr radius:
A) Increases | B) Decreases (1/Z) | C) Stable | D) Zero -
Time period (T) vs n:
A) n | B) n┬▓ | C) n┬│ | D) 1/n -
Series Limit means nтВВ is:
A) 1 | B) 2 | C) Infinite | D) Zero -
Energy in n=2 for He+ рдЖрдпрди?
A) -13.6 eV | B) -3.4 eV | C) -54.4 eV | D) -13.6 eV -
Unit of 'h' same as:
A) Energy | B) Momentum | C) Angular momentum | D) Power -
Levels -10eV, -5eV, -2eV. Which photon NOT possible?
A) 5eV | B) 3eV | C) 8eV | D) 4eV -
Size of what was found from Rutherford experiment?
A) Atom | B) Electron | C) Nucleus | D) Molecule -
Transition n=4 to n=2 series:
A) Lyman | B) Balmer | C) Paschen | D) Brackett -
Wave number (1/╬╗) of 1st Lyman line:
A) R | B) 3R/4 | C) 5R/36 | D) 8R/9
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