The discovery of electrons came about in a roundabout way. In the latt

Question

The discovery of electrons came about in a roundabout way. In the latter part of the 19th century, a popular demonstration by lecturers involved the cathode ray. They would evacuate air from the tube, pass high voltage through it, and show audiences the patterns of light that appeared. Were these really waves traveling through “ether”? Heinrich Hertz and Philipp Lenard conducted experiments that made this seem possible. On the otherhand, English physicists had long posited that there must be a fundamental unit of electricity, a particle that connected matter and electricity. The Irish physicist George Johnstone Stoney had even gone so far as to calculate its size and to name it electron.

French physicist Jean Perrin determined that the cathode rays had negative charges. But it wasn’t until English physicist J. J. Thomson designed an elegant set of experiments that the electron’s existence was proved.

The first experiment determined that the negative charge of cathode rays could not be separated from the rays themselves using magnetism. The second found that the rays could bend when influenced by an electric field. The third measured the ratio of charge to mass of the rays by comparing the energy they carried and the amount of deflection possible when an electric field was introduced. Thomson discovered that the ratio was enormous, meaning that the rays were tiny or very highly charged or both.

His conclusions, published in 1897, were of the existence of a subatomic particle with a negative charge. It was not until Thomson’s son George proved that electrons, although particles, had many of the properties of a wave that the mysteries of the cathode ray were truly solved.

George Thomson’s concept of wave-particle duality, the notion that matter and light have properties of both waves and particles, was critical to the development of quantum mechanics. It was not a particularly new concept, having roots as far back as Isaac Newton’s insistence that light was composed of particles, which he called corpuscles, the very word J. J. Thomson used to describe the particles of atoms he found in cathode rays.     1 
 1. Which of the following examples is presented as evidence that J. J. Thomson’s theory about subatomic particles was not new?

(A) The work of George Johnstone Stoney
(B) The work of George Thomson
(C) The work of Heinrich Hertz
(D) The work of Philipp Lenard
(E) A popular demonstration by lecturers

2 
 2. Thomson’s first experiment indicated which of the following?

(A) Unlike most rays, cathode rays were negatively charged.
(B) Cathode rays could be diverted using electromagnetism.
(C) The ray’s negative charge was embedded within particles.
(D) Most subatomic particles are tiny and highly charged.
(E) Patterns of light form rays in the ether.

3 
 3. The discussion of corpuscles in the fifth paragraph shows primarily tha t

(A) people in the 1600s understood the parts of an atom
(B) Thomson borrowed a term from a much older theory
(C) atoms and blood cells are linked by similar structures
(D) Isaac Newton was trained as a medical doctor
(E) early investigators considered light a living being

4 
 4. The statement in the first paragraph that “the discovery of electrons came about in a roundabout way” indicates which belief on the part of the author?

(A) There is more to discover about electrons.
(B) Physicists had to use circular logic to come up with a theorem.
(C) Electrons could never have been discovered by a single scientist.
(D) Scientists ended up at the beginning when they searched for an answer.
(E) The discovery of electrons did not proceed step-by-step.

5 
 5. The tone of this passage suggests which about the author’s attitude?

(A) She considers J. J. Thomson a splendid scientist.
(B) She prefers Isaac Newton to more recent scientists.
(C) She would like to know more about George Thomson.
(D) She believes that English scientists surpass the French.
(E) She finds the lengthy process of discovery disheartening.

6 
 6. Which of these inventions most relies on wave-particle duality in its everyday workings?

(A) A vacuum cleaner
(B) A high-voltage electric line
(C) An electron microscope
(D) A shortwave radio
(E) An inkjet printer

frappuchino · Answer

Hi  Sajjad1994 
For Question five, 5. "The tone of this passage suggests which about the author's attitude?", I went with D which states that the English scientists surpass the French.

I understand that this an extreme answer choice to go for, but the passage does state that while the French physicist did make some discovery, it wasn't until the English physicist JJ Thompson designed the elegant set of experiments.

Could you please explain how option A stands correct?

Vishal_Jain · Answer

Hello  anureetjuneja 
The author may state that " French physicist did make some discovery, it wasn't until the English physicist JJ Thompson designed the elegant set of experiments" but this doesnt signify anything about author's stance wrt to french scientists.

The author doesnt draw a comparison between English and French scientists anywhere.

Just because French scientists didnt contribute as much as English scientist  under the research on electrons , doesnt mean English scientists  on whole  surpass French counterparts.

Hope my explanation helps.

Sajjad1994 · Answer

In the passage, J. J. Thomson is portrayed in a positive light, as his experiments are described as elegant and crucial to proving the existence of electrons. The passage states,  "But it wasn’t until English physicist J. J. Thomson designed an elegant set of experiments that the electron’s existence was proved."  This portrayal suggests that the author holds a favorable view of J. J. Thomson as a scientist.

Additionally, the passage mentions J. J. Thomson's conclusions and his son George's contributions to the understanding of wave-particle duality. By highlighting these aspects, the author emphasizes the significance of J. J. Thomson's work and implies admiration for his scientific achievements.

Therefore, based on the positive depiction and emphasis on J. J. Thomson's experiments and conclusions, it can be inferred that the author considers J. J. Thomson a splendid scientist.  Option (A)  is the correct answer.

adityashikhar4 · Answer

Can I get an explanation for questions 2 and 6? In question 2, the charge being embedded within the particle (option c) does not seems to be even implicitly mentioned in the passage.

Ruchi007 · Answer

Sajjad1994  How to attempt #6 when one doesn't know the workings of these?

Sajjad1994 · Answer

Explanation

2. Thomson’s first experiment indicated which of the following?

Explanation

(A) Unlike most rays, cathode rays were negatively charged. 
The passage does not explicitly mention the comparison of cathode rays with other rays in Thomson's first experiment. The experiment focused on determining the ratio of charge to mass of the rays.

(B) Cathode rays could be diverted using electromagnetism. 
The passage does not mention electromagnetism as a factor in Thomson's first experiment. It states that the rays could bend when influenced by an electric field, not specifically electromagnetism.

(C) The ray’s negative charge was embedded within particles.  
This answer choice accurately represents the findings of Thomson's first experiment. The passage states that Thomson's first experiment determined that the negative charge of cathode rays could not be separated from the rays themselves using magnetism. This implies that the negative charge was embedded within particles.

(D) Most subatomic particles are tiny and highly charged. 
The passage mentions Thomson discovering that the ratio of charge to mass of the rays was enormous, suggesting that the rays were either tiny or highly charged or both. However, this conclusion is not specifically mentioned as part of Thomson's first experiment.

(E) Patterns of light form rays in the ether. 
The passage mentions demonstrations involving patterns of light in relation to cathode rays, but it does not connect these patterns of light to Thomson's first experiment.

Considering the information provided, the correct answer is  (C)  The ray’s negative charge was embedded within particles. Thomson's first experiment indicated that the negative charge of cathode rays could not be separated from the rays themselves using magnetism, suggesting that the negative charge was indeed embedded within particles.

Answer: C

Sajjad1994 · Answer

Explanation

6. Which of these inventions most relies on wave-particle duality in its everyday workings?

Explanation

The invention that most relies on wave-particle duality in its everyday workings is (C) an electron microscope.

Wave-particle duality is a fundamental concept in quantum mechanics that suggests that particles, such as electrons, can exhibit both wave-like and particle-like behavior. This means that they can have characteristics of both waves and particles depending on the experimental setup.

An electron microscope is a powerful scientific instrument used to visualize and study objects at the nanoscale. Unlike traditional optical microscopes that use light waves, electron microscopes use a beam of accelerated electrons to create images with much higher resolution.

In an electron microscope, the electron beam acts both as a particle and a wave. When accelerated to high speeds, electrons behave as particles, carrying kinetic energy and interacting with the atoms of the sample being examined. This interaction results in the scattering or absorption of the electrons by the sample.

However, due to the wave-particle duality, electrons also exhibit wave-like properties. The electron beam, while traveling through the microscope, undergoes diffraction and interference effects similar to waves. These effects are responsible for producing detailed and magnified images of the sample.

The resolution and imaging capabilities of an electron microscope depend on the wave-like properties of the accelerated electrons. The wavelength of the electrons determines the level of detail that can be observed. Smaller wavelengths enable higher resolution, allowing scientists to examine atomic and molecular structures in great detail.

Therefore, an electron microscope relies heavily on the wave-particle duality of electrons to produce clear, high-resolution images. It is the only option among the given choices that directly utilizes this concept in its everyday functioning.

Answer: C

partha7268 · Answer

can i get the explanation for question no 1 ?

Posted from my mobile device

Sajjad1994 · Answer

Explanation

1. Which of the following examples is presented as evidence that J. J. Thomson’s theory about subatomic particles was not new?

Explanation

The passage explains that J. J. Thomson's theory about subatomic particles, specifically the existence of electrons, was not new. It mentions that the Irish physicist George Johnstone Stoney had already proposed the idea of a fundamental unit of electricity and had even calculated its size and named it electron. This indicates that the concept of subatomic particles, including electrons, predated J. J. Thomson's work.

The passage also mentions the experiments conducted by Heinrich Hertz and Philipp Lenard, which made the possibility of waves traveling through "ether" seem plausible. However, these experiments are not presented as evidence that J. J. Thomson's theory was not new. Similarly, the work of George Thomson (J. J. Thomson's son) is mentioned as being critical to the development of quantum mechanics and the concept of wave-particle duality, but it does not suggest that J. J. Thomson's theory was not new.

Therefore, the correct answer is (A) The work of George Johnstone Stoney, as it demonstrates that the idea of subatomic particles, including electrons, predated J. J. Thomson's contributions.

Answer: A

Anandanwar · Answer

Hello,

For Q4 how do we reject D.
My analysis:
D: The passage mentions a question in the beginning of the passage: "Were these really waves traveling through ???ether????". Electrons are also mentioned for English physicists and Irish physicist George Johnstone Stoney.
And at the end we go towards that duality of electrons.

Sajjad1994 · Answer

Option (D)  is not the most accurate interpretation of the author's belief because it suggests a circular or recursive process where scientists didn't make progress. The phrase  "ended up at the beginning"  implies a lack of advancement or a return to the starting point.

In contrast, the passage conveys that there was progress in understanding electrons, moving from initial demonstrations to experiments by various scientists, and ultimately to J. J. Thomson's definitive experiments that proved the existence of electrons. The journey was not a repetition of the starting point but a cumulative process with each step contributing to the understanding of electrons. Therefore,  option (D)  does not align with the description of the discovery process presented in the passage.

The discovery of electrons came about in a roundabout way. In the latt

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The discovery of electrons came about in a roundabout way. In the latt

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