SBI Clerk or Junior Associate Exam Model Paper 6

Question Numbers: 9-16Directions: Read the following passage carefully to answer the questions that follow. Each question has five alternatives as its answer. Choose the correct option based only on the information provided or implied in the passage.In the soot-stained basement of Cambridge’s Cavendish Laboratory during the freezing spring of 1897, experimental physicist Dr. Arthur Pendelton found himself locked in a bitter ideological war against continental orthodoxy. The reigning scientific consensus, championed by prominent German physicists Heinrich Hertz and Philipp Lenard, asserted that the mysterious "cathode rays" glowing inside evacuated glass tubes were nothing more than ethereal waves—immaterial ripples in the luminiferous ether, akin to ultraviolet light. Pendelton, however, working alongside laboratory director J.J. Thomson, suspected something far more radical: that these luminescent green beams were actually high-speed streams of negatively charged, material particles torn from the very fabric of the atom itself. To prove this corporeal hypothesis, Pendelton constructed an advanced, ultra-high-vacuum Crookes tube fitted with dual parallel aluminum deflection plates and a sensitive zinc-sulfide phosphorescence screen at the terminal end.This intricate vacuum instrumentation offered unprecedented analytical precision, though it _________ severe occupational hazards for the researchers locked in the damp subterranean vault. To generate the electrostatic propulsion required to fire the beams, Pendelton had to operate massive Ruhmkorff induction coils at upwards of 50,000 volts, creating constant, deafening electrical arcing across the damp tables. Worse still, when the high-velocity cathode rays slammed into the glass walls of the vacuum tubes, they produced an intense, invisible secondary radiation—a newly discovered phenomenon known as Röntgen rays or X-rays. Within weeks of continuous exposure, Pendelton and his laboratory assistants developed "Crookes Erythema"—a painful, blistering cutaneous dermatitis accompanied by chronic lethargy, temporary blindness, and localized hair loss caused by the unshielded radiation bombarding their skin.On a tempestuous evening in late April, Pendelton finally achieved a technical milestone that had eluded his continental rivals: using a modified mercury-drop pump, he evacuated the glass tube to a vacuum so profound that virtually all residual gas molecules were expelled. This was the critical breakthrough; in previous experiments by Hertz, residual gas inside the tube had ionized under the electric field, forming a conductive screen that masked the electric force and falsely made the rays appear immune to electrostatic deflection. With the interfering gas removed, Pendelton energized the aluminum plates. Instantly, the vibrant green spot on the zinc-sulfide screen shifted decisively toward the positive plate—irrefutable proof of negative electric charge. Calculating the deflection angle against the magnetic field strength, Pendelton derived the mass-to-charge ratio of the mysterious entity. He stared at his ledger in disbelief: the particles were nearly two thousand times lighter than the hydrogen atom, the smallest piece of matter then known to science. He realized with a profound sense of awe that they had not merely settled an academic debate about glowing glass tubes; they had shattered the ancient Greek dogma of the indivisible atom, discovering the electron and unlocking the subatomic universe.