SAT Reading - Khan Diagnostic Quiz level 1 - reading 3

Questions 1-5 are based on the following
passage.


Passage 1 is excerpted from Michael Thackeray’s “The Long, Winding Road to Advanced Batteries for Electric Cars,” published in 2012. Passage 2 is excerpted from Julie Chao’s “Goodbye, Range Anxiety? Electric Vehicles May Be More Useful Than Previously Thought,” published in 2015.




Passage 1


Batteries have come a long way since Alessandro Volta

first discovered in 1800 that two unlike metals, when

separated by an acidic solution, could produce an electric
current. In their evolution, batteries have taken on various
5 forms, ranging from lead-acid, to nickel-metal hydride, to

current-day lithium-ion.
Now, technological advances in batteries are more critical

than ever. Coupled with the alarming rate at which we are

exploiting fossil fuels, the world’s growing energy demand
10 necessitates that we find alternative energy sources.
With present-day technology, however, electric vehicles

cannot compete with internal combustion vehicles.

According to [one] review, “energy densities two and five

times greater are required to meet the performance goals of a
15 future generation of plug-in hybrid-electric vehicles (PHEVs)

with a 40-80 mile all-electric range, and all-electric vehicles

(EVs) with a 300-400 mile range, respectively.” To make the

leap, scientists will have to find new couplings of battery

materials.
20 Still, researchers are hopeful of a breakthrough. They can

now use computing to accelerate the discovery of new

electrode and electrolyte systems. This creates a positive

feedback loop in which computing informs experiments, and

experimental results help refine the computing process. This
25 high-throughput iterative process may be scientists’ ultimate

hope for discovering materials that can significantly improve

the electrochemical performance, safety and cost of batteries.


Passage 2


With today’s electric vehicle (EV) batteries, “end of life”

is commonly defined as when the storage capacity drops
30 down to 70 to 80 percent of the original capacity. As capacity

fades, the vehicle’s range decreases. Berkeley researchers

decided to investigate the extent to which vehicles still meet

the needs of drivers beyond this common battery retirement

threshold.
35 The Berkeley scientists analyzed power capacity fade, or

the declining ability of the battery to deliver power, such as

when accelerating on a freeway onramp, as it ages. They

modeled the impact of power fade on a vehicle’s ability to

accelerate as well as to climb steep hills and complete other

drive cycles. They found that power fade for the chosen

vehicle [a Nissan Leaf] does not have a significant impact on

an EV’s performance, and that a battery’s retirement will be

driven by energy capacity fade rather than by power fade.
The researchers thus conclude that “range anxiety may be
45 an over-stated concern” since EVs can meet the daily travel

needs of more than 85 percent of U.S. drivers even after

losing 20 percent of their originally rated battery capacity.

They also conclude that batteries can “satisfy daily mobility

requirements for the full lifetime of an electric vehicle.”

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Question 1 Which situation is most similar to the “positive feedback loop” (lines 22–23) described in Passage 1?