During the Twelfth Century, the Indian Author Bhaskara Published a Drawing of a Wheel

Reading Passage Question

During the twelfth century, the Indian author Bhaskara published a drawing of a wheel with an odd number of sealed containers of mercury around its outer rim. According to the designer, as the wheel spun the cylinders of mercury would spin with it. Each time a cylinder reached the top of the wheel, gravity would pull the mercury from one side of the container to the other and exert a continuous downward force on the wheel, thus enabling it to turn perpetually without external energy. This scheme marked the first documented attempt to design a perpetual motion machine. Like the study of alchemy, the notion of perpetual motion machines has enticed inventors with the impossible for centuries; since Bhaskara’s proposal, countless designers, through either fraud or wishful thinking, claimed to have devised similar contraptions.

By definition, a perpetual motion machine is a device that can operate continuously and supply useful work with no external power source. While processes in nature such as the carbon or hydrologic cycles appear to be perpetual, they are in fact driven by the energy of the sun in the same way that a hydroelectric power plant is driven by the external power of a waterfall. Perpetual motion machines, on the other hand, are designed to harness the potential energy of gravity, buoyancy, or other physical forces in a perfectly efficient manner that essentially recycles energy.

The science that studies the behavior and rules of energy is thermodynamics. In terms of thermodynamics, there are two types of perpetual motion machines. The first is a machine that provides more energy than it requires, which violates the first law of thermodynamics: energy can neither be created nor destroyed. In the case of Bhaskara’s design, the second law of thermodynamics is violated. The second law asserts that in all energy transfers in a closed system, the potential energy after the transfer will be less than the initial potential energy, with the difference lost to dissipative forces such as drag or friction in the form of heat. Each time the mercury in Bhaskara’s wheel strikes the side of the containers, the impact generates heat, which is dissipated into the air and thus lost from the system. Because of this, 100 percent efficiency cannot be achieved and the machine will eventually come to rest.

“During the twelfth century, the Indian author Bhaskara published a drawing of a wheel” - is a GMAT reading comprehension passage with answers. Candidates need a strong knowledge of English GMAT reading comprehension.

This GMAT Reading Comprehension consists of 3 comprehension questions. The GMAT Reading Comprehension questions are designed for the purpose of testing candidates’ abilities in understanding, analyzing, and applying information or concepts. Candidates can actively prepare with the help of GMAT Reading Comprehension Practice Questions.

Solution and Explanation

Question 1
The primary purpose of the passage is to:

1. illustrate erroneous designs of early scientists who did not possess a proper knowledge of the laws of physics
2. show why the overbalanced wheel cannot be made to do usable work
3. discuss the pursuit and ultimate failure of inventors to design a perpetual motion machine
4. argue that while perpetual motion cycles are possible in nature, scientists have never been able to produce a working mechanical model
5. reject a design for a perpetual motion machine and propose a working alternative

Question 2
It can be inferred from the passage that:

1. Bhaskara rejected the validity of the laws of thermodynamics when he designed the overbalanced wheel.
2. Bhaskara’s design of the overbalanced wheel included 100 percent efficiency as one of its fundamental principles.
3. Bhaskara’s design of the overbalanced wheel constituted a scientific fraud that was not revealed until centuries had passed.
4. Bhaskara believed that the overbalanced wheel would work because he had not actually produced a working model.
5. Bhaskara designed the overbalanced wheel to demonstrate the impossibility of perpetual motion machines.

Question 3
In paragraph two, the author discusses the carbon and hydrologic cycles in order to:

1. refute the notion that perpetual motion is only possible in technological ventures
2. illustrate how only sunlight can successfully power perpetual motion cycles
3. elaborate on the definition of perpetual motion machines through apparent examples
4. argue that hydroelectric power plants are not, in fact, perpetual motion machines
5. demonstrate that perpetual motion machines are not designed using solar energy

Question 4
The third paragraph supplies information for answering all of the following questions EXCEPT:

1. What is the dissipative force that acts upon Bhaskara’s design of the overbalanced wheel?
2. Which law of thermodynamics is broken by Bhaskara’s design of the overbalanced wheel?
3. How does Bhaskara’s design fail to achieve totally efficient recycling of energy?
4. How might a machine violating the first law of thermodynamics be designed?
5. What is the purpose of the science of thermodynamics?

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