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Hint

1

Define electric current

the flow of charges in a wire through a cross section per unit time (ampere)

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2

electric current formula

I=q/t (Ampere A)

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3

define ohms law

the current flowing through a conductor is directly proportional to the potential diff across its ends (volts)

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4

ohms law formulas

V=IR, R=V/I (volts-V)

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5

Resistance (def/formulas)

property of conductors to resist the flow of current (ohms)

r= ρ l/a (ohms-Ω)

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6

Define thermal velocity

the velocity in which free electrons randomly move with high speeds (10^5m/s) in a metal. The avrg thermal velocity in wire is zero

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7

Define Drift velocity

the velocity in which free electrons move with when a potential diff is applied across the conductor in the opposing direction of the electric field

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8

Drift velocity formula

Vd=-eE/m τ

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9

What is the relationship b/w current and drift velocity in a conductor?

i=neAVd

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10

define relaxation time

the time interval b/w successive collisions of electrons with the positive ions in the metallic lattice

τ=λ / Vrms

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11

Define mobility

magnitude of drift velocity per unit electric field applied

μ=Vd/E (m² s^-1 v^-1)

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12

Define Current density

The amount of current flowing through the conductor per unit cross-sectional area

J=i/a

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13

Conductance

measure of ease of flow of electrons in conductor Reciprocal of resistance (G)

G=1/R (Siemen-S)

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14

temperature dependance of resistance

R(T) = R₀ [1 + α (T - T₀) ]

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15

temperature dependance of resistivity

ρ(T) = ρ₀[1 + α (T - T₀)]

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16

Define Cells

A device which converts chemical energy into electrical energy. Its a source of constant voltage but not current

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17

EMF of cells

the potential difference across the cell when it’s not supplying any current (volts)

E=V+Ir

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18

Potential Difference of a cell

The potential diff across the the cell when its supplying current to the external resistance (volts)

V=E-Ir

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19

Internal Resistance

The obstruction/resistance in the electrolyte of the cell in the path of electric current

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20

What does the internal resistance of a cell depend on?

The internal resistance of a cell depends on factors such as the electrolyte concentration (α C), temperature (α 1/T), and electrode area (α 1/A).

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21

Current in the cell formula (relation b/w V, I, and R)

I=E/R+r

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22

What is Kirchhoff's junction rule or current law?

Kirchhoff's junction rule states that the total current entering a junction in a circuit must equal the total current leaving the junction.

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23

What is Kirchhoff's loop rule, also known as the voltage law?

Kirchhoff's loop rule states that the sum of the voltages around any closed loop in a circuit must equal zero.

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24

Wheatstone bridge Formula

if balanced i.e galvanometer readings shows 0

p/q=r/s that is ps=rs

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25

Electric Energy (def+formula)

The work done by any source to maintain the electric current in the circuit

E=VIT=I²RT=TV²/R (Joules-J)

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26

Electric Power (def+formula)

Its the rate of work done by a source

P=W/t=VI=Vq/t (Watt-W)

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27

Electrical Heating

When current I flows through conductor of resistor R in time t, heat produced is

H=i²Rt (Joule) =i²Rt/4.18 cal

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