Subjective Assignment
BOARD LEVEL QUESTIONS ON CONCEPT OF DRIFT VELOCITY, OHM’S LAW
Q.1
Is electric current scalar or vector?
Q.2
What is the SI unit of e.m.f.?
Q.3
Write the dimensional formula for e.m.f.
Q.4
Is e.m.f. a scalar or a vector quantity?
Q.5
In a conductor there are a large number of electrons free to move in the body of it. Assuming there is one free electron per atom, what is the order of free electrons per cubic meter of copper?
Q.6
What is the order of random velocity of electrons of an isolated metallic conductor at room temperature?
Q.7
What is the relationship between electric current and drift velocity?
Q.8
How does electric field vary with drift velocity?
Q.9
What is the order of resistance of human skin ?
Q.10
What is needed to cause an electric current ?
Q.11
How many electrons pass through a certain cross section of a conductor through which 1 amp current is flowing?
Q.12
Compare the drift speed of electrons of copper with the thermal speed of copper atoms at ordinary temperatures.
Q.13
A current of 1 A flows through a copper wire. Calculate the number of electrons passing through any cross-section of the wire in 1.6 s? Do all the electrons of each copper atom contribute to the current?
Q.14
Define electric current. Give its units and dimensions.
Q.15
Define the e.m.f. of a battery and differentiate between the potential difference and e.m.f of the battery.
Q.16
Define drift velocity. Give its order in a conductor.
Q.17
Define the relaxation time and give its order in a good conductor.
Q.18
Name the carriers of electric current in:
(i) a bar made of silver,
(ii) a germanium semiconductor,
(iii) a superconductor, and
(iv) a hydrogen discharge tube.
Q.19
If the drift velocity is very small then how do we get
(a) instant current
(b) large amount of current.
Q.20
Differentiate between ohmic and nonohmic conductor with at least three examples of each with their graphs.
Q.21
A steady current is passing through a conductor of nonuniform cross-section then state that out of the following quantities which will remain constant
(a) current
(b) current density
(c) electric field
(d) drift speed.
Q.22
Through a certain cross-section of a discharge tube 2×105 electrons and 4×106 protons cross in opposite direction in a time of seconds.Find the current passing through this cross-section.