It is currently 28 May 2020, 03:07

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# QOTD #19 Quantum mechanics is a relatively new field of phys

Author Message
TAGS:
Founder
Joined: 18 Apr 2015
Posts: 11158
Followers: 237

Kudos [?]: 2785 [0], given: 10592

QOTD #19 Quantum mechanics is a relatively new field of phys [#permalink]  23 Jul 2016, 01:04
Expert's post
00:00

Question Stats:

90% (03:18) correct 10% (04:48) wrong based on 20 sessions
Quantum mechanics is a relatively new field of physics that was developed in the early 1900’s. Although we classically think of a particle as a fixed object, quantum mechanics describes particles as waves using properties such as position and energy. The quantum mechanical wave describes the probability of a particle to attain certain values of these properties, and measuring the particle samples from this probability. Take, for example, the analogy of rolling a six-sided die. For each roll there is a one-in-six chance that any single number will result. After rolling,however, only one single number will be observed.If the die is rolled enough times, one can deduce that the die has six sides and that each side is equally likely. However, one can never be completely sure, because rolling dice is probabilistic in nature. Quantum mechanics states that the same is true of the position (and other properties) of a particle. A particle trapped in a closed box has some finite probability of being at any location within the box. Open the box once and you’ll find the particle at only one location. Open the box enough times and you’ll see all the particle locations and the frequency at which they are achieved. From this, one can deduce the original properties of the quantum mechanical wave, just as one could deduce the properties of the die.

The counterintuitive properties of quantum mechanics, that the attributes of a particle cannot be known in advance of measurement, initially provoked many strong philosophical debates and interpretations regarding the field. In fact, Einstein was deeply troubled by the idea of nature being probabilistic and commented famously that, “God does not play dice with the universe.” Over the last 70 years, however, irrefutable evidence has abounded that verifies the truth of the theory of quantum mechanics.
Which of the following best expresses the main idea of the passage?

(A) Particles are not a fixed object but rather waves.
(B) Controversial theories are often found to be correct.
(C) Quantum mechanics correctly postulates the probabilistic nature of particles.
(D) Many questions still exist about the nature of particles and quantum mechanics.
(E) Experiments can be designed to test the quantum mechanical nature of particles.

[Reveal] Spoiler: OA
C

Based on the information in the passage, which of the following would best explain Einstein’s motivation for stating that “God does not play dice with the universe”?

(A) Einstein did not believe that particles should be governed by probability as in a game of dice.
(B) Einstein believed that God should control the fate of the universe.
(C) Einstein was opposed to the theory of quantum mechanics on the grounds that it violated causality.
(D) Einstein’s religious beliefs did not allow him to fully understand the theory of quantum mechanics.
(E) Einstein believed that God created the universe such that particles would be modeled probabilistically as in quantum mechanics.

[Reveal] Spoiler: OA
A

Consider each of the answer choices separately and indicate all that apply.

Which of the following can be properly inferred based on the information in the passage?

• The location of a particle within a closed box cannot be known for certain without observing theparticle.
• Properties such as position and energy of a particle can never be measured.
• Particles can be properly described as quantum mechanical waves.

[Reveal] Spoiler: OA
I and III ony

_________________

Need Practice? 20 Free GRE Quant Tests available for free with 20 Kudos
GRE Prep Club Members of the Month: Each member of the month will get three months free access of GRE Prep Club tests.

Manager
Joined: 23 Jan 2016
Posts: 133
Followers: 4

Kudos [?]: 144 [1] , given: 15

Re: QOTD #19 Quantum mechanics is a relatively new field of phys [#permalink]  30 Jul 2016, 04:37
1
KUDOS
1. The passage starts with explaining quantum mechanics and end with the sentence "however, irrefutable evidence has abounded that verifies the truth of the theory of quantum mechanics". So main idea of the passage is C

2. " Einstein was deeply troubled by the idea of nature being probabilistic and commented famously that, “God does not play dice with the universe.”", Answer choice A summarizes this point.

3. I and III, "Open the box once and you’ll find the particle at only one location. Open the box enough times and you’ll see all the particle locations and the frequency at which they are achieved". So Choice I is true. "The quantum mechanical wave describes the probability of a particle to attain certain values of these properties" We can infer Choice III

"The quantum mechanical wave describes the probability of a particle to attain certain values of these properties, and measuring the particle samples from this probability."contradicts answer choice II, hence false.
Intern
Joined: 23 Sep 2017
Posts: 46
Followers: 0

Kudos [?]: 10 [0], given: 2

Re: QOTD #19 Quantum mechanics is a relatively new field of phys [#permalink]  28 Feb 2018, 05:29
Got it
Re: QOTD #19 Quantum mechanics is a relatively new field of phys   [#permalink] 28 Feb 2018, 05:29
Display posts from previous: Sort by