Question

Question 4 a) Two 8k resistors are connected as a potential divider with a supply p.d. of 20 mv. What is the current flowing and the p.d. across each resistor? (5 mark) b) The circuit shows four arrangements A, to D of three 2uF capacitors which arrangement has the smallest capacitance, the largest capacitance. (5 mark) Total 10 marks Space to answer Question 4 here А HAHE D HA

please, answer all questions

Answer 1

4) a) the resistors will be potential divider only when they are connected in series

Equivalent resistance = R1 + R2 = 8 + 8 = 16 kΩ

Current = V/R = 20 / 16000 = 0.00125 A = 1.25 mA

pd across resistor =IR = 0.00125*8 = 10 V

and it will be the same across the other resistor also

b) for figure A

1/C = 1/2 + 1/2 + 1/2

C = 0.67 uF

For figure B

C = 2 + 2 + 2 = 6 uF

for figure C

C1 = 2*2 / 2 + 2 = 1 uF

C(equi) = 1 + 2 = 3uF

for figure D

C1 = 2 + 2 = 4uF

2 and 4 uF are in series

C = 2*4 / (2 +4) = 1.67 uF

so A has the smallest capacitance and B has the largest capacitance