- a voltmeter
- a milliammeter
- a micrometer screw gauge (to be shared)
- a stopwatch
- a centre zero galvanometer
- a switch
- ten connecting wires (at least with a crocodile clip on one end)
- a resistance wire mounted on a millimetre scalelabeled AB
- a resistance wire labeled P
- a resistance wire labeled Q
- a capacitor labeled C
- a metre rule or half metre rule
- two dry cells and a cell holder
- a carbon resistor labeled R

Proceed as follows:

**PART A**

- Using the micrometer screw gauge provided, measure the diameter:
- D of wire P.

D = _________________ (1 mark) - d of wire Q

d = _________________ (1 mark)

- D of wire P.
- Determine C
_{1}the value of the ratio D/d

C_{1}= __________________ (1 mark) - Set up the circuit as shown in
**figure 1**. (*Ensure that each of the wires P and Q is 50 cm long*)

Close the switch. Using the clip at the the free end from the wire from the galvanometer, tap wire**AB**near end**A**and observe the defection in the galvanometer. - Then tap the wire near end
**B**and then observe the deflection in the galvanometer. - Now tap the wire
**AB**at various points between**A**and**B**to obtain a point**K**where there i no deflection in the galvanometer.- Determine the length
**L**_{1}, the distance from**A**to**K**.

L1 = ________________ (1 mark) - Determine the length
**L**_{2}, the distance from**B**to**K**.**L**_{2}= ______________ (1 mark)

- Determine the length

- Set up the circuit as shown in
- Given that resistance
**R**_{Q}of**Q**is 9.0 ohms, determine the resistance**R**_{P}of**P**using the expression: (2 marks) - Determine the value of
**C**_{2}given that, (2 marks) - Compare the value of
**C**_{1}(in part (b)) with that of**C**_{2}. (1 mark)**PART B**

- Given that resistance
- Set up the circuit shown in
**figure 2**. S and T are crocodile clips.- Charge the capacitor
**C**by connecting the crocodile clip to**S**. Record the reading of the voltmeter,**V**V = _____________ (1 mark) - Calculate the value of current of I
_{o}, given that I_{o}= V/R (where R = 4.7 x 10^{3 }Ω) (3 marks)

- Charge the capacitor
- Discharge the capacitor by by disconnecting the crocodile clip from
**S**and connecting it to**T**. Observe and record the highest reading of the milliammeter I_{1}. (This is the current at t_{0}= 0).

(You may have to repeat the process to obtain an accurate value.)

I_{1}= _______________ (1 mark) - Recharge the capacitor by connecting the crocodile clip to
**S**. - Discharge the capacitor and at the same time start the stop watch to measure the time
**t**_{1}taken for the current to decrease to the half the value of**I**_{1}ie (^{1}/_{2}I_{1})**t**_{1}= ______________ (1 mark)

- Discharge the capacitor by by disconnecting the crocodile clip from
- Recharge the capacitor and repeat the procedure in f(iii) to measure the time
**t**_{2}taken for the the current to decrease to one tenth of the value of**I**_{1}i.e (^{1}/_{10}I_{1})**t**_{2}= _____________ (1 mark) - Use the values of the currents corresponding times to draw a graph of current I (y axis) on the grid provided. (3 marks)

- Recharge the capacitor and repeat the procedure in f(iii) to measure the time