Current Electricity

Question 1

The flow of current through a conductor is due to

Answer 1

Free electrons

Question 2

The specific resistance of wire depends upon

Answer 2

material

Question 3

A wire is stretched to double its length, its resistance will be

Answer 3

Four times

Question 4

the unit of specific resistance is

Answer 4

Ohm meter

Question 5

Is copper wire an Ohmic resistance

Answer 5

Yes

Question 6

In Semiconductor on raising temp. what happens to its resistance

Answer 6

decreases

Question 7

the conductance of super conductor is

Answer 7

infinite

Question 8

the e.m.f. of a cell depends upon

Answer 8

nature of electrolyte and electrodes

Question 9

Kirchoff’s first law is in accordance with

Answer 9

Law of conservation of charge

Question 10

the internal resistance of a cell can be decreased by:

Answer 10

decreasing the distance between electrodes.

Question 11

THE PROPERTY WHICH DIFFERENTIATES BETWEEN 2 DIFFERENT KINDS OF CHARGES IS CALLED

Answer 11

POLARITY OF CHARGE

Question 12

WHY GOLD LEAF ELECTROSCOPE IS USED ?

Answer 12

TO DETECT CHARGE ON BODY

Question 13

DEFINE CONDUCTOR

Answer 13

THOSE WHICH ALLOWS ELECTRICITY TO PASS THRIUGH THEM EASILY ARE CALLED CONDUCTORS

Question 14

DEFINE INSULATORS

Answer 14

THOSE MATERIALS WHO DONT LET ELECTRICITY PASS THROUGH THEM ARE INSULATORS

Question 15

DEFINE EARTHING OR GROUNDING

Answer 15

THE PROCESS OF SHARING CHARGE TO EARTH IS CALLED EARTHING GROUNDING

Question 16

IN INDUCTION CHARGING SPHERES ARE

Answer 16

EQUALLY AND OPPOSTIVELY CHARGED

Question 17

NO . OF ELECTRONS IN 1COULONB CHARGE

Answer 17

6X10^18

Question 18

A CUBIC PIECE OF COPPER OF SIDE 1CM CONTAINS ABOUT— ELECTRONS

Answer 18

2.5X10^24

Question 19

COULOMB LAW

Answer 19

I DONT THINK I NEED TO WRITE THIS

Question 20

VALUE OF K AND UNIT

Answer 20

9X13^9
NM^2/C^2

Question 21

VALUE OF PERMITTIVITY OF FREE SPACE

Answer 21

E0 = 8.854X10^-12 N-1 M-2

Question 22

ELECTRIC FILED

Answer 22

Qq/
4⊓E0 r^2

Question 23

SI UNIT OF ELECTRIC FEILD

Answer 23

N/C

IT IS A VECTOR QUANTITY

Question 24

DIRECTION OF ELECTRIC FEILD

Answer 24

FOR+VE RADAILLY OUTWARDS
FOR-VE RADAILLY INWARDS

Question 25

DIRECTION OF ELECTRIC FEILD LINES

Answer 25

START FROM +VE AND END AT -VE

Question 26

FIELD OF ELECTRIC DIPOLE

Answer 26

FOR POINTS ON AXIS -VE = E =-QP/4⨅E0(R+A)2 +VE= E = QP/4⨅E0(R-A)2 FOR POINTS ON EQUITORIAL PLANE E=-P/4⨅E0R3

Question 26

ELECTRIC FLUX

Answer 26

∆∅=E∆SCOS⩉

Question 26

SI UNIT OF ELECTRIC FLUX

Answer 26

N/CM2

Question 26

P=

Answer 26

QX2A

Question 26

DEFINE ELECTRIC DIPOLE

Answer 26

AN ELECTRIC DIPOLE IS A PAIR OF EQUAL AND OPPOSITE POINT CHARGES Q AND -Q SEPARTED BY 2a

Question 26

FIELD DUE TO UNIFORMLY CHARGED INFINITE PLANE SHEET

Answer 26

E = σ /2 E0

Question 26

TORQUE CU OF UNIFORE ELECTRIC FELID

Answer 26

ɽ=q E 2aSIN⩉=pxE

Question 26

FEILD DUE TO UNIFORMLY CHARGED THIN SPHERICAL SHELL

Answer 26

OUTSIDE -- E = Q/4⨅E0R2 INSIDE -- E = 0

Question 26

FEILD DUE TO INFINITELY LONG STRAIGHT WIRE

Answer 26

E = ʎ/2⨅E0r

Question 26

DEFINE SURFACE CHARGE DENSITY

Answer 26

Suppose q is the charge and a is the area of the surface over which it flows, then the formula of surface charge density is σ = q/A, and the S.I. unit of surface charge density is coulombs per square meter (cm−2).

Question 26

DEFINE LINEAR CHARGE DENSITY

Answer 26

Per unit length i.e. linear charge density, where q is the charge and is the length over which it is distributed. The SI unit will be Coulomb \(m ^ {-1}\). FORMULA --ʎ=∆Q/∆L

Question 26

DEFINE VOLUME CHARGE DENSITY

Answer 26

Per unit volume i.e. volume charge density, where q is the charge and V is the volume of distribution. The SI unit is Coulomb \(m ^ {-3}\). FORMULA -- P=∆Q/∆V

Question 26

DEFINE GAUSS LAW

Answer 26

Gauss's law for electricity states that the electric flux Φ across any closed surface is proportional to the net electric charge q enclosed by the surface; that is, Φ = q/ε0, where ε0 is the electric permittivity of free space

Question 26

IMPORTANT PROPERTIES OF FEILD LINES ARE

Answer 26

1] FIELD LINES ARE CONTINOUS CUVERS WITHOUT ANY BREAKAGE 2] TWO FIELD LINES NEVER INTERSECT E/O 3] THEY START FROM +VE TO-VE 4] THEY DO NOT FORM CLOSED LOOP

Question 27

DEFINE ELECTRIC CURRENT

Answer 27

Electric Current is the rate of flow of electrons in a conductor. The SI Unit of electric current is the Ampere.

Question 28

DEFINE INOSPHERE

Answer 28

IN NATURE FREE CHARGED PARTICLES DO EXIST LIKE IN UPPER STRATA OF ATMOSPHERE CALLED INOSPHERE

Question 29

WRITE OHM LAW

Answer 29

V = I R

Question 30

WRITE FORMULA OF RESISTANCE

Answer 30

R = P L / A P IS RESISTIVTY

Question 31

FORMULA OD CHARGE DENSITY

Answer 31

J = I /A J = σE σ IS CONDUCTIVITY

Question 32

RELATION B/W CONDUCTIVITY AND RESISTIVITY

Answer 32

σ= 1/P

Question 33

DEFINE DRIFT VELOCITY

Answer 33

When electrons are subjected to an electric field they do move randomly, but they slowly drift in one direction, in the direction of the electric field applied. The net velocity at which these electrons drift is known as drift velocity.

Question 34

FORMULA OF DRIFT VELOCITY

Answer 34

I = n v A Q

Question 35

DEFINE MOBILITY

Answer 35

The drift velocity of an electron for a unit electric field is known as the mobility of the electron ⋃= Vd /E

Question 36

RESISTOR COLOUR CODES

Answer 36

READ FROM NCERT

Question 37

TEMPTURE DEPANDANCE OF RESISTIVITY

Answer 37

ρT= ρ0 [1 + a(T–T0)]

Question 38

FORMULA OF ELECTRICAL ENERGY

Answer 38

dK = I Vdt

Question 39

electrical power

Answer 39

P = I 2 R = V 2/R = I V

Question 40

RESISTANCE IN PARALLEL

Answer 40

Req=1/R1+1/R2....

Question 41

RESISTANCE IN SERIES

Answer 41

Req=R1+R2....

Question 42

DEFINE ELECTROMOTIVE FORCE EMF

Answer 42

V+ – (–V–) = [V+]+ V– . This difference is called the electromotive force (emf) of the cell and is denoted by e.

Question 43

DEFINE INTERNA REISTANCE

Answer 43

The electrolyte through which a current flows has a finite resistance r, called the internal resistance

Question 44

V=

Answer 44

= e – I r

Question 45

The maximum current that can be drawn from a cell is for R = 0

Answer 45

Imax = e/r

Question 46

REVISE KHRICOOF LAW WHEATSTONE BRIDGE

Answer 46

Junction rule: At any junction, the sum of the currents entering the junction is equal to the sum of currents leaving the junction Loop rule: The algebraic sum of changes in potential around any closed loop involving resistors and cells in the loop is zero

Question 47

CONDITON FOR BALANCE WHEATSTON BRIGDE

Answer 47

R1/ = R3/ R2 = R4

Question 48

STUDY METER BRIDGE AND POTENTIOMETER