SCIENCE 9 FINAL Flashcards

1
Q

What is biomass?

A

Biomass- organic matter, such as food or agricultural waste, used as an energy source

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2
Q

What are the kinds of energy found in a D-Cell?

A

Chemical & Electrical

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3
Q

What is Ohm’s Law?

A

Ohm’s Law states that-

> The resistance of a conductor stays constant

> The current is directly proportional to the voltage applied

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4
Q

Electrolyte

A

A paste or liquid that conducts electricity because it contains chemicals that form ions

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5
Q

What is the difference between a Dry Cell and a Wet Cell?

A

A dry cell’s electrolyte is in form of a paste. They are generally sealed

A wet cell’s electrolyte is in liquid form (ex. Sulfuric Acid)

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6
Q

What is a cell?

Why isn’t a cell a battery?

A

A cell is a device capable of generating electrical energy from chemical reactions

A battery is a set of cells

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7
Q

What is electroplating?

A

Coating a metal with a thin layer of silver or gold

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8
Q

What is electrolysis?

A

Decomposition of a substance by an electric current (split into individual elements)

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9
Q

What is an electrical discharge?

A

Sudden transfer of electrical charge from one object to another, indicated by a spark

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10
Q

Electromagnet

A

Coil of insulated wire that becomes a magnet when current flows through it

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11
Q

Electrochemistry

A

The study of chemical reactions involving electricity

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12
Q

Why does lightning hit a tree before a golf club on the ground?

A

Lightning wants to take the quickest path to the ground

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13
Q

Why are lightning rods installed on to tall buildings?

A

Tall buildings are a natural target for lightning. Installing these rods causes the discharge to be conducted harmlessly to the ground

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14
Q

Superconductors

A

Conductors that have no resistance to electron flow. However these substances need to be at impractical temperatures for every day use

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15
Q

What is resistance measured in?

A

Ohms (Greek Letter Omega)

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16
Q

What is current measured in

A

Amperes (A)

17
Q

What is power measured in?

A

Watts (w)

kilowatts (kW)

18
Q

What is energy measured in?

A
Joules (J)
Mega joules (MJ)

Kilowatt Hours (kW•h)

kW= W/1000

19
Q

What is time measured in?

A

Seconds (s) for joules

Hours (h) for kilowatt hours

20
Q

Why can’t a device be 100% efficient? (unless it is an electric heater!)

A

There will always be wasted energy (Mostly heat energy due to friction)

21
Q

Why are electric engines more efficient than combustion engines?

A

Electric engines have less moving parts therefore less friction. This results into less wasted energy

22
Q

What is geothermal energy?

A

It is the energy derived from the internal heat of Earth

23
Q

What is a rheostat or variable resistor?

A

Resistor whose resistance can be changed by adjusting the portion of the resistor the current travels through