Page 135 - Science Class 06
P. 135
Look at the picture of a dry cell which p at the center of the base. These two
consists of a zinc container having a paste form the terminals.
of ammonium chloride. In the centre, a v When electricity is passed through the
carbon rod is fi ed with a metal cap and terminals of the bulb, the filament gets
wrapped in a muslin cloth bag, kept in its heated up and produces light.
centre, which contains a mixture of
v A bulb is said to be fused if the filament
powdered coke, graphite, zinc chloride and
gets broken. Fused bulb doesn’t glow.
manganese dioxide. The cell is completely
v The two terminals do not directly touch
sealed from the top.
each other to avoid short circuit.
+ve
Terminal Metal Cap (Top) v Filling a bulb with an inert gas such as
argon or nitrogen will not burn the
Carbon Rod Sealant tungsten filament.
Zinc Can
Aluminum Foil Coated Paper 1. What are the two different types of
charges?
2. What is a cell?
Anode Material 3. What is the basic difference between
(MnO₂, ZnCl₂, etc.) –ve
Terminal Tin-plate (Bo om) voltaic cell and dry cell?
4. Why do we fill an inac ve gas inside an
Dry Cell
electric bulb?
When the two terminals, i.e., carbon rod
and the zinc container of the dry cell are FLOW OF ELECTRIC CURRENT
connected with a bulb the current starts We can define electric current as the rate of
flowing and the bulb glows. flow of electrons in a conductor. The
Electric Bulb protons are ghtly packed inside the
An electric bulb is a device which produces nucleus of an atom whereas electrons in the
light when electricity is passed through its outer shells orbits around the nucleus. Since
terminals. electrons are loosely held by the nucleus,
they are able to travel freely within the
v The bulb has two thick contact wires in
limits of the body. The SI Unit of electric
the center with a thin wire a ached
current is the Ampere.
between them. This thin wire is called
filament. ELECTRIC CIRCUIT
v One of the thick wires is connected to Electric circuit is an inter connected
the metal case at the base of the bulb combina on of conductors, switch and
and the other is connected to the metal source of electricity. A diagram of a simple
circuit is given on the next page.
Science-6 135
