Physics 9702/34 — October/November 2018

You have been provided with the circuit shown in Fig. 1.1.

• Select one of the groups of parallel resistors and connect it in the component holder.
• Connect the resistor R and the component holder in series between X and Y to complete the circuit shown in Fig. 1.2.

• Ensure that switch S is in position 2.
• Record the number $n$ of parallel resistors in the component holder.

$n$ = ______

• Close switch A.
• Record the voltmeter reading $V$.

$V$ = ______

• Open A.

• Close A.
• Move S to position 1 and start the stopwatch. The voltmeter reading will immediately become negative and then gradually increase.
• Stop the stopwatch as soon as the voltmeter reading passes zero and becomes positive.
• Record the time $t$ as shown by the stopwatch.

$t$ = ______

• Move S to position 2.
• Open A.

By using different groups of resistors, change $n$ and repeat (b) until you have six sets of values of $n$ and $t$.

Record your results in a table. Include values of $\frac{1}{n}$ in your table.

It is suggested that the quantities $t$ and $n$ are related by the equation

where $a$ and $b$ are constants.

Use your answers in (d)(iii) to determine the values of $a$ and $b$. Give appropriate units.

$a$ = ______

$b$ = ______