Quantum Theory, although of tremendous scientific value, has neverthel

Quantum Theory, although of tremendous scientific value, has nevertheless prompted debate among physicists. The debate arose because quantum theory addresses the peculiar properties of minute objects such as photons and electrons. While one type of experiment shows that these objects behave like particles, with well-defined trajectories through space, another demonstrates that, on the contrary, they behave like waves, their peaks and troughs producing characteristic “interference” effects. However, scientists have failed to devise an experiment to demonstrate both behaviors simultaneously.

In the 1920s, two alternate interpretations of quantum theory attempted to resolve this apparently contradictory wave-particle duality. Physicists Niel Bohr argued that wave particle properties are not contradictory, but complementary. Contrary to our intuition that an object continues to exist in some determined form even though we cannot perceive it, he concluded that the physical reality of a quantum objects is actually determined before the object is observed via experiment.

Physicists Werner Heisenberg's “uncertainty principle”, by contrast, postulated that we cannot precisely determine two complementary properties, such as position and momentum, of a quantum object simultaneously: if we measure an object's position with absolute certainty, then there is an infinite uncertainty in its momentum, and vice versa. He concluded that although we are limited in our ability to measure objects at the atomic and subatomic levels, their position and momentum are nonetheless defined all along.

1) Which of the following does the passage mention as providing evidence of the dual nature of quantum objects?

a) Scientists' inability to measure the position and momentum of quantum objects simultaneously.
b) Scientists' inability to measure the momentum of the quantum objects with certainty.
c) The similarities in the appearance of particles and waves.
d) The tendency of quantum objects to exhibit well-defined trajectories only at either extremely high or extremely low speeds.
e) The behavior of quantum objects as either particles or waves depending on the type of experiment that is performed.


2) It can be inferred from the passage that if scientists were able to measure the position and momentum of quantum objects precisely and simultaneously, then the

a) theory that the dual properties of quantum objects are complementary would be proven.
b) basic postulate of the uncertainty principle would be refuted
c) distinction between particle behavior would cease to exist
d) debate about quantum theory among physicists would be unchanged.
e) trajectories of quantum objects through space would be more difficult to predict.


3) All of the following are mentioned in the passage as possible characteristics of quantum objects except:

a) a minute size
b) momentum
c) position in space
d) sporadic movement
e) wave like behavior


4) Which of the following, if true, would most seriously undermine Bohr's conclusion about the physical reality of a quantum object?

a) The physical properties of particles and waves are inherently complementary.
b) Human intuition is not a factor in the interpretation of scientific data about quantum objects.
c) Results of experiments on quantum objects are sometime influenced by the expectations of the experiments.
d) The technology used in research on quantum objects has made tremendous advances since the 1920s.
e) Quantum objects posses distinct, continuously existing physical forms that do not depend on the experiments used to measure them


5. Q. The passage suggests that the debate among physicists mentioned in the first sentence has arisen in part because

A. the rapid movement of quantum objects poses an insurmountable obstacle to precise measurement
B. scientists have been unable to devise a single experiment that reveals both particle and wave properties of quantum objects simultaneously
C. the controversial nature of quantum theory has made it difficult for scientists to agree on what evidence is acceptable
D. division among physicists has resulted in the design of experiments that produce unintelligible experimental results
E. research efforts have been undermined by irreconcilable contradictions between equally compelling interpretations of quantum theory


6. Which of the following best describes the organization of the passage?

A. A thesis is introduced and then amended.
B. Arguments are presented, weighed, and then reconciled.
C. A problem is described and different interpretations intended to resolve the problem are presented.
D. Hypotheses are analyzed, their premises are refuted, and alternatives are suggested to replace the hypotheses.
E. A theory is advanced, opposing evidence is considered, and the theory is abandoned.