9. Electricity

Question 1

electric current
charge
formula

Answer 1

flow of charge carriers

charge on charge carriers is quantised

e≈1.6×10^−19 C
Q = It

A proton’s charge +e and an electron’s charge −e are the smallest indivisible units of electric charge. This means that all electric charges in nature are combinations of these elementary charges. so only whole no. ‘e’ eg. 1e, 2e.

Question 2

current-carrying conductor formula

Answer 2

I = Anvq,

I- current
A- cross-sectional area
n- number density of charge carriers ( per unit volume)
v- drift velocity
q- charge of a single charge carrier=e value- 1.6*10^-19

Question 3

potential difference

Answer 3

potential difference across a component- energy transferred per unit charge from electrical to other forms

Question 4

potential difference and power formula

Answer 4

V = W/Q
V=IR

P = IV
P = I^2*R
P = V^2 / R

Question 5

resistance

Answer 5

potential difference per unit current

Question 6

I–V characteristics of a metallic
1. conductor at constant temperature
2. a semiconductor diode
3. a filament lamp

Question 7

resistance of a filament lamp

Answer 7

resistance of a filament lamp increases as current increases because its temperature increases. (all proportional and here current and resistance are NOT inversely proportional- exception)

Question 8

state Ohm’s law

Answer 8

1. current through a conductor is directly proportional to potential difference across the conductor or vice versa.
2. provided that temperature remains constant.

Question 9

resistivity of a material with formula

Answer 9

R = ρL/A

R- resistance of the material- ohm
ρ- resistivity of the material- ohm meter
L- length of the conductor- m
A- cross-sectional area of the conductor- m^2

Question 10

light-dependent resistor

Answer 10

resistance of a light-dependent resistor (LDR) decreases as the light intensity
increases

Question 11

thermistor

Answer 11

resistance of a thermistor decreases as the temperature increases