Download Electrical Energy II

Electrical Energy
1. Define closed circuit.
A closed circuit is a circuit that allows electrons to pass
through the circuit.
2. Identify the part of an electric circuit in which electrical
energy is changed into other useful forms of energy.
The light globe in a circuit changes the electrical energy into
light.
3. Explain why metals are better conductors than nonmetals.
Because most non-metals are insulators and most metals are
conductors, so the metals are better because they are
conductors.
4. Explain why a 50-watt globe glows more brightly than
a 25-watt globe.
Because a 50-watt globe lets a higher amount of voltage and
current pass through it.
5. Identify what takes place inside a battery to cause an
electrical current to flow.
When a device is connected to a battery it causes a chemical
reaction that generates electrical energy. This is known as
an electrochemical reaction.
6. Outline why lithium-ion batteries are commonly used
in laptops and mobile phones.
The lithium-ion batteries are used because they provide 3.6
Volts, more than twice the standard AA Alkaline battery and
yet they are compact and rechargeable. Hence, they are
commonly used in laptops and mobile phones.
7. Explain why it is important to have circuit symbols that
are recognised by scientists and electricians around the
world.
Circuit diagrams are used to communicate the type of
electric components included in a circuit and how those
components are arranged in the circuit. In circuit diagrams,
internationally accepted symbols are used to represent each
circuit component. Straight lines are used to represent the
wire leads connecting the components.
8. Identify which of the following arrangements will allow
the globe to light up.
A, because both wires are connected to the outlet of the
globe, allowing the electrical energy to pass through.
9. a) If the filament of globe A breaks, do globes B and C
remain lit or do they stop working?
They would remain lit because there are two circuits, with
globe A only in the first, so the current would go around A
and head to B and C.
b) If the filament of globe B breaks, which globe or globes (if
any) remain lit?
Only A would remain lit because it is a different circuit to B
and C.
c) If the filament of C breaks which would stay alight?
Only A would remain lit because it is a different circuit to B
and C.