current electricity

Question 1

inst current

Answer 1

dq/dt

Question 2

drift velocity

Answer 2

-eEtime(avg)/m

Question 3

Drft velocity in terms of V

Answer 3

eVt/ml

Question 4

relationship between I and Vd

Answer 4

I=VdenA

Question 5

mobility

Answer 5

-et/m=Vd/E

Question 6

resistivity formula

Answer 6

ml/ne²tA

Question 7

relationship between T and R for conductors, semi conductors and alloys

Answer 7

cond. - directly proportional
semi cond- inverse
alloys- no effect

Question 8

resistance and temp coefficient formula

Answer 8

Rf=Ro(1+alphadeltaT)

Question 9

temperature coefficient is positive for _ and negative for _

Answer 9

cond, semi cond

Question 10

current density

Answer 10

i=J.A

Question 11

ohms law vector form

Answer 11

J=Esigma

Question 12

relation between resistivity and mobility

Answer 12

rho=1/ne(mu)

Question 13

cells do or do not produce charge

Answer 13

no

Question 14

terminal voltage is?

Answer 14

Potential difference across two terminals of cell when current is drawn
V=E-Ir

Question 15

i in terms of internal resistance and emf

Answer 15

i=E/r+R

Question 16

factors on which r depends (int. R)

Answer 16

area of electrodes (inverse), dist between electrodes (direct), concentration of electrolytes (direct), temperature (direct)

Question 17

kirchhoffs laws

Answer 17

junction rule and loop rule

Question 18

power is

Answer 18

Vi

Question 19

combination of cells in series E and r

Answer 19

E=E1-E2
r=r1+r2

Question 20

cells combination parallel E and r

Answer 20

E=(E1/r1+E2/r2)/(1/r1+1/r2)

Question 21

for mixed grouping, equivalent E, r and i are?

Answer 21

En, nr/m, Emn/nr+mR

Question 22

max power transfer theorem

Answer 22

power transferred to the load is max when ext load resistance becomes equal to equivalent int r

Question 23

meter bridge formula

Answer 23

unknown R X=(100-l)R/l

Question 24

potentiometer uses

Answer 24

measuring potential diff, emf of cell, comparing emf, finding int r

Question 25

principle of potentiometer

Answer 25

potential diff across a wire is directly proportional to length if the wire is of homogeneous material, has uniform cross sec area, constant current flows

Question 26

formula of V based on potentiometer

Answer 26

V=Kl
where K= irho/area

Question 27

formula to calculate emf of cell (potentiometer)

Answer 27

E1=(Er/r+R)×l/L

Question 28

relation between E and l to compare emfa

Answer 28

E directly proportional to l and E1/E2=l1/l2

Question 29

int resistance formula using shunt

Answer 29

r=(l1-l2)/l2×S
l1>l2

Question 30

_ velocity determines the current in a conductor

Answer 30

drift

Question 31

drift velocity is due to

Answer 31

motion of conduction electrons due to electric field

Question 32

dependence of Vd on E (ohms law)

Answer 32

Vd=E

Question 33

example of non ohmic resistance

Answer 33

diode

Question 34

E,J, rho relation

Answer 34

E=Jk