Electricity and Circuits Video Lecture | Science Class 6

0:0:0: starting with your house electricity is
0:0:3: important for operating all appliances
0:0:5: be it for entertainment lighting and of
0:0:8: course all
0:0:9: technology do you know where this
0:0:12: electricity comes from this electricity
0:0:15: comes from a power station but what if
0:0:18: the electricity fails or is not
0:0:20: available at some places at those places
0:0:24: we might need to use a torch here is
0:0:27: when an electric cell comes in an
0:0:30: electric cell is used to provide
0:0:32: electricity to a torch which in turn
0:0:34: produces light when we observe the
0:0:37: electric cell closely we see that it has
0:0:39: a metal cap on one side and a metal disc
0:0:42: on the other with positive and negative
0:0:45: signs on the ends this means that the
0:0:48: cell has two terminals namely positive
0:0:51: and
0:0:52: negative the side with the metal cap is
0:0:54: a positive terminal and the side with
0:0:57: the metal disc is a negative terminal an
0:1:0: electric cell uses the chemicals inside
0:1:2: it to produce
0:1:4: electricity when the chemicals inside it
0:1:6: are used up it stops producing
0:1:9: electricity now let's look at the bulb
0:1:12: in the torch
0:1:13: closely observe what happens when the
0:1:16: bulb of the torch is turned on did you
0:1:19: see a thin wire inside the bulb started
0:1:21: giving off light this thin wire is
0:1:25: called the filament of the bulb it is
0:1:27: joined with two thicker wires to give
0:1:30: Port one of these thick wires is
0:1:32: connected to the metal case at the base
0:1:35: of the bulb the other thick wire is
0:1:38: connected to the metal tip at the center
0:1:40: of the base the base of the bulb and the
0:1:43: metal tip of the base are the two
0:1:45: terminals of the bulb Let's do an
0:1:47: activity where we will try to light up a
0:1:50: bulb using an electric cell for this we
0:1:53: need a bulb electric wires plastic
0:1:56: rubber and an electric cell remove the
0:1:59: plastic from the end of the wires and
0:2:2: cover the cell using a rubber band in
0:2:4: this manner first let's connect both the
0:2:6: wires to one side of the bulb you will
0:2:9: observe that the bulb doesn't light up
0:2:12: observe that there are similar marks of
0:2:14: positive and negative on the cell as
0:2:17: well as the bulb first we'll connect the
0:2:20: plus sign of the cell to the plus sign
0:2:22: of the bulb and minus sign of the bulb
0:2:24: to the minus sign on doing so the bulb
0:2:28: turns on now try reversing the terminals
0:2:32: plus with minus and minus with plus even
0:2:35: now the bulb turns
0:2:38: on this type of arrangement where both
0:2:41: terminals of the cell are connected to
0:2:43: both terminals of the bulb is called an
0:2:45: electric circuit the bulb blows only
0:2:48: when current flows through the
0:2:50: circuit but you must have seen that
0:2:53: sometimes even when the bulb is
0:2:55: connected to the cell it doesn't turn on
0:2:58: why is this
0:3:0: this may happen if the Bulb Has fused an
0:3:3: electric bulb May fuse due to many
0:3:6: reasons one reason for a bulb to fuse is
0:3:9: a break in its filament a break in the
0:3:12: filament of an electric bulb means a
0:3:14: break in the path of the current between
0:3:16: the terminals of the electric cell
0:3:19: therefore a fused bulb does not light up
0:3:22: as no current passes through its
0:3:24: filament we had an arrangement for
0:3:26: turning on or off our homemade torch by
0:3:29: moving moving the base of the bulb away
0:3:31: from The Wire of the cell this
0:3:33: arrangement of turning on and off a
0:3:35: circuit is called a switch we can make
0:3:38: another simple and easier switch to use
0:3:41: in our
0:3:42: circuit let's try making a switch to
0:3:44: turn on and off the circuit let's add a
0:3:47: key to the circuit and now join the
0:3:50: other end to the key the bulb will turn
0:3:53: on as soon as we touch the key with the
0:3:56: wire this is because an iron key allows
0:3:59: elect electricity to flow through it and
0:4:1: completes the circuit so any object
0:4:4: which allows electricity to flow through
0:4:6: it is called a
0:4:8: conductor therefore the iron key is a
0:4:11: conductor whereas when we replace the
0:4:14: iron key with a piece of cloth the bulb
0:4:17: doesn't turn on so any object which
0:4:20: doesn't allow electricity to flow
0:4:22: through it is called an
0:4:24: insulator therefore cloth is an
0:4:27: insulator we hope that you have
0:4:29: understood the concept of electricity
0:4:31: and
0:4:32: circuits now here's a secret on how you
0:4:35: can study effectively with the urv app
0:4:38: you can learn with chapter notes watch
0:4:40: video lectures and solve ncer based McQ
0:4:44: tests of this chapter on
0:4:46: urv and that's not all you also get
0:4:49: amazing courses for cl 6 and much more
0:4:52: for your CL 6
0:4:54: preparation thank you