Does the bulb glow
(Yes/No)
S.No. Object
Yes
118
Table 2
Name of the
Material
1.
Hair pin
Metal
2.
Pencil lead
3.
Eraser
Rubber
4.
Plastic scale
Plastic
5.
Match stick
6.
Divider from
geometry box
7.
Piece of paper
8.
Iron nail
9.
Piece of Metal bangle
10.
Piece of Glass bangle
11.
Paper clip
12.
Piece of chalk
13. Safety pin
If you look at table 2, after recording your
observations you will find that the bulb
glows in some cases and does not glow in
other cases. Can you guess the reason?
Substances which allow electric
current to flow through them are known
as conductors of electricity,
Substances which do not allow
current to flow through them ar
as insulators
Using the above definitions, can y
the objects you observed in your
as conductors and insulators? M
Michael Faraday (1791-1867), an English chemist and physicist, developed
primitive electric motor,
Answers
Answer:
Radhe Radhe
Question 1:
Choose from the options (a), (b), (c) and (d) given below the figure which shows the correct direction of current.
Solution:
(b) Current always starts from positive terminal and end at negative terminal of the battery. This is conventional direction of flow of current in a circuit.
Question 2:
Choose the incorrect statement.
(a) A switch is the source of electric current in a circuit
(b) A switch helps to complete or break the circuit
(c) A switch helps us to use electricity as per our requirement
(d) When the switch is open, there is an air gap between its terminals
Solution:
(a) A switch cannot be a source of electric current in the circuit. Electric cell is a source of electricity in the circuit. Other options are the functions of a switch.
Question 3:
In an electric bulb, light is produced due to the glowing of
(a) the glass case of the bulb (b) the thin filament
(c) the thick wires supporting the filament (d) gases inside glass case of the bulb
Solution:
(b) In an electric bulb, its thin filament glows and gives off light and heat.
Question 4:
In the following arrangement shown in figure, the bulb will not glow if the ends A and B are connected with
(a) a steel spoon (b) a metal clip (c) a plastic clip (d) a copper wire
Solution:
(c) Since, a plastic clip is an insulator, so current will not pass through it and bulb will not glow in this case. However, a steel spoon, a metal clip and a copper wire are conductors of electricity.