Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Cee > Electric Current PHYSICS MODULE 3 > Flashcards

Electric Current PHYSICS MODULE 3 Flashcards

1
Q

The electric current is due to the flow of
a. Positive Charge only
b. Negative charge only
c. Both positive and negative charge
d. Neutral particles only

A

c. Both positive and negative charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The electric current in a metallic conductor is due to the flow of
a. Electrons only
b. Electrons and positive only
c. Positive ions only
d. Neutral atoms only

A

a. Electrons only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The electric current in a liquid is due to the flow of
a. Electrons only
b.positive ions only
c. Negative and positive ions
d. Electrons and positive ions

A

c. negative and positive ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The electric current in a discharge tube containing a gas is due to
a.Electrons only
b.positive ions only
c. negative and positive ions
d.electrons and positive ions

A

a.Electrons Only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Electric current is a
a. scalar quantity
b. vector quantity
c.sometimes scalar and sometimes vector
d. number only

A

a. scalar quantity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which one is correct?
a. flow of charge is current
b.rate of flow of charge is called current
c.rate of doing work is
d. current rate of current is current.

A

b. rate a flow of charge is called current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the SI unit of electric current ?
a.A
b.N
c.Z
d.Up

A

a.A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

If q=t²+4t+5,find I inst at t=3sec
a.10A
b.7A
c.8A
d.0A

A

a.10A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

A 10⁹ electrons pass through a cross section of a conductor in 10-³ sec what is the current in Ampere?
a.1.6x10-⁷A
b.1.77x10⁷A
c.22.x10-⁵A
d.not possible

A

a.1.6x10-⁷A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

If P=t²+1,then find q flow through a cross section between 0 to 3 sec.Also find the no.of e- that flows in this time.
a.12C,7.5x10-⁹C
b.14,7x10-¹⁹C
c.14C,12C
d.none

A

a.12C,7.5x10-⁹C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The drift velocity of electrons is of the order of
a.1m/s
b.10-⁴m/s
c.10⁶m/s
d.10-⁹m/s

A

b.10-⁴m/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The thermal speed(random motion)of electrons is of the order is
a.1m/s
b.10-³m/s
c.10⁵m/s
d.3x10⁸m/s

A

c.10⁵m/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In metal conductors of electricity is due to
a.free electrons
b.bound electrons
c.Ions
d.Atoms

A

a.free electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the average velocity of electron when no potential is given to a conductive
a.0
b.1
c.2
d.1.5

A

a.0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Formula of drift velocity

A

Vd=I/neA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Formula of current density

A

J=I/A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which one is vector quantity
a.Current
b.Current Density
c.Charge
d.Mass

A

b.Current Density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

A wire has non-uniform cross section.It carries a current i.Then the drift velocity of electron :-
A •o————0 •B

a.remains constant from A to B
b.Decreases on moving from A to B
c.increases on moving from A to B
d.first increase then become comstant

A

b.decreases on moving from A to B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

A steady current is passing through a linear conductor of non- uniform cross section. The current density in the conductor is

a.Independence of cross section b.directly proportional to area of cross section
c.Inversely proportional to area of cross section
d. inversely proportional to the square root of area of cross section

A

c.inversely propertional to area of cross section

20
Q

My mistake question
A steady current passing through a linear conductor of non uniform cross section .The current in the conductor is :-
a.independent of area of cross section
b.directly proportional to the length of conductor
c.directly proportional to area of cross section
d. inversely proportional to length of the conductor

A

a.independent of area
Kinaki current density haina current cha

21
Q

Formula of resistance

A

R=V/I
V: potential difference
I: electric current

22
Q

Unit of resistance

A

Ohm

23
Q

Ohms law formula

A

V=IR

24
Q

Resistance of conductor is ________for ohmic conductor

A

Constant

25
Q

Ohmic conductor example

A

Silver
Copper wire
Nichrome wire
Gold

26
Q

Non ohmic conductor

A

Diodes
Semi conductor
Filaments of lamp
Transistors

27
Q

Formula of resisance interms of resistivity

A

R=ρ (rho) L/A

28
Q

A wire of length ‘l’ has resistance R.This wire is stretched to twice it’s original length find it’s new resistance.
a.R/2
b.2R
c.R/4
d.4R

A

d.4R

29
Q

When length increases by 2 times area
a.Increases by 2 times A/2
b.Decreases by 2 times A/2

A

b.Decreases by 2 times A/2

30
Q

A wire of resistance ‘R’ is compressed to half of it’s original length.Find it’s new resistance.
a.2R
b.R/2
c.R/4
d.4R

A

c.R/4

31
Q

A wire of resistance 3ohm is stretched to 10 times it’s original length.Find new resistance.

A

R’=n²R
=10²x3
=100x3
=300ohm

32
Q

If a wire of resistance R I’d stretched n times the resistance becomes
a.n²/R
b.R/n²
c.nR
d.n²R

A

d.n²R

33
Q

The wire of resistance 2ohm is stretched 2 times the resistance will be
a. 2 ohm
b.4 ohm
c.8 ohm
d.7 ohm

A

c.8 ohm

34
Q

A wire of resistance 2 ohm is stretched 1.5 time the resistance of stretched wire becomes
a.1.5ohm
b.3.5ohm
c.6 ohm
d.4.5 ohm

A

d.4.5 ohm

35
Q

Resistivity ρ (rho) depends upon

A

Temperature
Materials

36
Q

The electrical resistance of metals
a.increase with increase with temperature
b.decrease with increase in Temperature
c.is independent of temperature
d.increases for some metals and decreases fo others

A

a.increase with increase with temperature

37
Q

Constantan wire(Resistance constant) is used for making Standard resistance because it has
a.low sp.resistance
b.high sp.resistance
c.Negligible temperature coefficient of resistance
d.High melting point

A

c.Negligible temperature coefficient of resistance

38
Q

If n,e,T and m represent electron Density,charge,relaxation time and mass of an electron respectively,then the resistance of a wire of length l and cross section are
a.ml/ne²TA
b.mTA/ne²l
c.ne²TA/ml
d.ne²l/TA

A

a.ml/ne²TA

39
Q

A piece of aluminium and germanium temperature is increased from T1K to T2K. Then resistance is:-
a. Each of them increases
b. Each of them decreases
c. Aluminium increases germanium decreases
d. Aluminium decreases germanium increases

A

c. Aluminium increases germanium decreases

40
Q

Resistivity of alloy=R alloy .The resistivity of
constituent metals=R metals. Then usually
a.Ra>Rm
b.Ra=Rm
c.R a<R>=<=R metal</R>

A

d.R alloy>=<=R metal

41
Q

Conductivity is the
a reciprocal of current density b.reciprocal of resistivity
c. reciprocal of resistance
d. same as current

A

b.reciprocal of resistivity

42
Q

The specific resistance resistivity of a wire varies with
a. length
b. cross section
c.mass
d.material

A

d.material

43
Q

To wire A and b are made up of copper. Both wires are 1 m long but why are a is 1 mm take and wire B is 2 mm thick the specific resistance is
a .more for A
b.same for both A and B
c. cannot be compared
d. same for both a and b

A

b same for both A and B

44
Q

Numerical
A piece of copper wire has resistance are. It is stretched to half of its radius. The new resistance of copper wire becomes
a.R
b.R/4
c.R/16
d.16R

A

c.16R

45
Q

Why are resistance 5.5 ohm is drawn and uniformly so that its length increases twice. Then the new resistance is
a.5.5Ohm
b.11Ohm
c.22Ohm
d.44Ohm

A

c.22ohm

46
Q

The resistance of wire for 4ohm when it is spent through 180° and twisted together then new resistance will be:-
a.1ohm
b.2ohm
c.4ohm
d.8ohm

A

a.1ohm

47
Q

One of the following is an Ohmic conductor
a.Transistor
b.Vacuum Tube
c.Electrolyte
d.Nichrome wire

A

d.Nichrome wire

Cee (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions