Honolulu star-bulletin. [volume] (Honolulu [Oahu, Hawaii]) 1912-2010, 1916-11-04
ELECTRICAL TO CHEMICAL
ON CHARGE AND
CHEMICAL TO ELECTRICAL
ON DISCHARGE


the first point one unit of electrical
of electricity which is moved. This
unit of electrical work is called the
joule. The quantity of electricity in
coulombs passing through circuit in a
certain time is equal to the product
of the steady current in amperes and
the time in seconds. For example, If a
storage battery when being charged
takes a current of four amperes the
quantity of electricity passing through
the battery in one hour, or 5000 sec
onds, will be equal to $4,000, or a.
400 coulombs. If the pressure between
the terminals of the battery is known,
then the work in charging the battery
for one hour will be equal to the pro-
duct of the quantity of electricity and
the Ealne of the. difference in cleo
trical level through which it is raised.
Hence the work done in this particular
case is equal to 14,400X7, or 100,80
joules.
The same amount of work would be
done in charging battery If the cur
rent was two amperes and the battery
was on charge for two hours; IL the
current was one ampere and the bat
terry was on charge four hours, etc.
Likewise, the same amount of work
would be done if the current was eight
amperes, the pressure was 3.5 volts
and the battery was on charge for one
hour; If the current was two amperes.
the pressure IA volts and the battery
was on charge one hour, etc
What is the work done in operating
starting motor for two minutes If it
takes a current of $50 amperes from
six volt battery?
The quantity of electricity moved is
equal to the time in seconds, which is
60X2, or go seconds. multiplied by
the current in amperes.
Quantity is 12O%150=1S,000 cou-
lombs.
The work done will be equal to the
product of the electrical pressure and
the difference in electrical level
through which the electricity moves,
or 1S.0C0X7, which is equal to 10000
joules.
In this case the electricity does
work as it passes through the motor
because it is passing from a point Of
higher electrical pressure to a point
OF lover electrical pressure, or IT is
running down hill electrically.
The same amount of work would be
done in operating the motor for four
minutes If it took current of rs
amperes. in operating it for one min
ute if II took current of 300 amperes,
etc.
Energy
Energy may be defined as the abili-
ty to do work. Thus, the energy of a
certain quantity of water standing in
a pool in the street is zero with re-
spect to the street level, as it is not
capable of operating water wheel or
any other device when such a device
is on the same level as the water. If
the water contained in this pool be
raised to the roof of a building the
water then possesses some energy
with respect to the level of the street
and is capable of operating a water
wheel or any other device when such
device is on the street level or To-
Gated at any point below the level of
the water. The energy possessed by
the water with reference TO the street
level when II is raised to the top of
the building is equal to the work done
IN raising the water from the street
level 10 the top of the building.
For example, when 1900 gallons of
water are raised to the top of build
ing which is 100 feet above the level
OF the street the work done, we found
in the previous section. was 1000. 900
foot-pounds. The energy possessed by
this water, then. is 100000 foot
pounds. and it will do that amount of
work if allowed to fall to the street
level. 100 feet below. You can think of
work as being the expenditure of en-
ergy. and energy. of course. is the
ability to do work. The energy pos
sessed by 500 gallons of water which
have been raised a vertical height of
200 feet, 2400 gallons OF water which