9. A current of IA is drawn by a filament of an electric bulb. What would be
the number of electrons passing through a cross-section of the filament in 168?
Answers
Explanation:
The relationship between current, charge and time is given as follows.
charge = current x time, that is, Q = It where,
charge is Q, it is measured in coulombs (C)
current is I, it is measured in amperes (A)
time is t, it is measured in seconds (s).
The relationship between electronic charge, charge and number of electrons are protons is given as follows.
charge = number of electrons or protons x electronic charge, that is Q = ne
where,
charge is Q, it is measured in coulombs (C)
number of electrons/protons is n, it is measured in numbers
electronic charge is e, it has a standard value = 1.6×10
−19
Coloumbs (C).
Equating both the above equations, that is,
It = ne we get,n=
e
I×T
=
1.6×10
−19
1×16
=10
20
.
Hence, number of electrons passing through a cross section of the filament in 16 seconds would be roughly 10
20
.
Answer:
Explanation:
Given parameters
I = 1 A
t = 16 sec
e = 1.6 × 10-19 C
Current drawn by the filament can be calculated as
I = Q/t
Since Q = N × e
I = (N×e)/t
N = (I×t)/e
N = (1 × 16)/1.6 × 10-19
N = 10 x 1019
N = 1020