Electrical circuits

Question 1

Current (def, formula, units)

Answer 1

Rate of flow of charge
I = ΔQ/Δt
A amps

Question 2

Voltage (def, formula, units)

Answer 2

Energy supplied per unit charge
V=E/Q=Work done/Q
V volts or J/C joules/coulomb

Question 3

Resistance (def, formula, units)

Answer 3

a measure of the opposition to current flow in an electrical circuit.
R=V/I
Ω Ohms

Question 4

Ohm’s Law

Answer 4

V=IR
V=AΩ

Question 5

series voltage nd current

Answer 5

voltage used up by components V1+V2=V
current is constant A1=A2=A
R=R1+R2

Question 6

parallel circuits voltage and current

Answer 6

voltage is the same in all junctions V=V1=V2
current splits at junction takes the path of least resistance. charge per unit time is conserved I = I1+I2
1/R=1/R1+1/R2

Question 7

Ohmic resistors

Answer 7

wire, fixed resistor, variable resistors

Question 7

non ohmic resistors

Answer 7

diode, semiconductors, thermistor, LDR, light bulb
non linear

Question 7

Thermistors

Answer 7

non ohmic
cold = high R hot = low R
box with hockey stick

Question 7

Thermistor uses

Answer 7

Thermostat. Fridge. Fire Alarms

Question 8

LDR

Answer 8

Light dependent resistor
brighter / closer to source = lower resistance
darker / further from source = higher resistance

Question 9

LDR uses

Answer 9

Street lamps. Devices that measure light intensity. Burglar alarm

Question 10

Power

Answer 10

P=IV
P=E/t

Question 11

Energy

Answer 11

E=tP
E=IVt