Electricity As

Question 1

What is electric current?

Answer 1

The flow of charged particles.

Question 2

What is the formula for charge?

Answer 2

Q = It

Question 3

What is a coulomb?

Answer 3

Charge that flows when 1 ampere passes a point for 1 second.

Question 4

What does it mean that charge is quantised?

Answer 4

Charge exists in discrete packets

Question 5

What is potential difference?

Answer 5

Work done per unit charge between two points.

Question 6

What is the unit of potential difference?

Answer 6

Volt (1V = 1 J/C).

Question 7

What is the formula linking work

Answer 7

voltage and charge?

Question 8

What is electrical power?

Answer 8

Rate of energy transfer or work done per unit time.

Question 9

What are the three formulas for power?

Answer 9

P = VI

Question 10

What causes current in a conductor?

Answer 10

Drift of electrons due to applied potential difference.

Question 11

What is the formula for current using drift velocity?

Answer 11

I = Anvq

Question 12

In I = Anvq

Answer 12

what does ‘n’ represent?

Question 13

In I = Anvq

Answer 13

what does ‘v’ represent?

Question 14

What is resistance?

Answer 14

Ratio of potential difference to current

Question 15

What is the unit of resistance?

Answer 15

Ohm (Ω)

Question 16

What is Ohm’s Law?

Answer 16

Current is directly proportional to voltage if temperature is constant.

Question 17

What is an ohmic component?

Answer 17

A component that obeys Ohm’s Law (e.g.

Question 18

What is resistivity?

Answer 18

A material’s opposition to current flow; ρ = RA/L

Question 19

What is the unit of resistivity?

Answer 19

Ohm meter (Ωm)

Question 20

What is the resistance formula involving resistivity?

Answer 20

R = ρL/A

Question 21

What are the I–V characteristics of a metallic conductor?

Answer 21

Linear graph; V ∝ I if temperature constant.

Question 22

What happens to resistance in a filament lamp as voltage increases?

Answer 22

Resistance increases due to heating and ion collisions.

Question 23

What happens to resistance in a thermistor as temperature increases?

Answer 23

Resistance decreases because more electrons are released.

Question 24

What is a thermistor?

Answer 24

A resistor with resistance that decreases as temperature increases.

Question 25

What are the I–V characteristics of a diode?

Answer 25

Conducts in one direction after a threshold voltage; blocks in reverse.

Question 26

What is threshold voltage in a diode?

Answer 26

The minimum voltage required for it to conduct.

Question 27

What is an LDR (Light Dependent Resistor)?

Answer 27

A resistor whose resistance decreases as light intensity increases.

Question 28

How does resistance of an LDR change with light?

Answer 28

More light → less resistance.

Question 29

Give a real-world application of thermistors or LDRs.

Answer 29

Used in temperature or light sensors.

Question 30

Why does a filament lamp not follow Ohm's Law?

Answer 30

Because its resistance increases with temperature.

Question 31

What condition is required for Ohm’s Law to hold true?

Answer 31

Temperature must remain constant.