TEST OF PRACTICAL KNOWLEDGE QUESTION You ar..

Question 1 Report

TEST OF PRACTICAL KNOWLEDGE QUESTION

You are provided with a battery of e.m.f. E, a key K, a voltmeter, a standard resistor R$_{0}$ = 2$\Omega$, a resistance box R, and some connecting wires.

i. Measure and record the e.m.f. E of the battery.

i. Set up a circuit as shown in the diagram above with the key open.

iii. Set the resistance on the resistance box to R 22.

iv. Close the key, read and record the potential difference V on the voltmeter.

v. Evaluate V$^{-1}$

vi. Repeat the procedures for five other values of R = 5$\Omega$ 10$\Omega$,12$\Omega$,15$\Omega$ and 20$\Omega$. In each case, record V and evaluate V$^{-1}$

vii. Tabulate the results.

viii. Plot a graph with R on the vertical axis and V$^{-1}$ l on the horizontal axis, starting both axes from the origin (0,0).

ix. Determine the slope, s, of the graph and the intercept c on the vertical axis.

x. Calculate $\propto$ and $\beta$ from the equations s = R$_{0}$ $\propto$ and c= - (R$_{0}$+B).

xi. State two precautions taken to obtain accurate results.

Answer

R $_{0}$ = 2 $Ω$ , emf of the battery = 2.0V

Table of value

S/N	R $Ω$	V	V
1 2 3 4 5 6	2 5 10 12 15 20	4.70 2.40 1.75 1.40 1.10 0.76	0.214 0.417 0.571 0.714 0.909 1.320

Slope = $\frac{△ R}{△ V^{- 1}}$ = $\frac{30.00 - 0.00}{1.50 - 0.15}$

= $\frac{30.00}{1.35}$ = 22

Intercept on the horizontal axis = 0.15
Calculation of $\propto$

$\propto$ = $\frac{S}{R_{0}} = \frac{22}{2}$ = 11

Calculation of $β$
$β$ = -(R $_{0}$ + C) = - (2 + 0.15) = -(2.15) = -2.15

Precuations

- Key opened in between reading/key opened when readings were not taken.
- Tight connections ensured
- Avoided parallax error when taking reading on voltmetre
- Repeated readings shown on table
- Noted/corrected zero error on voltmetre
- Clean terminals ensured.

(b)

i. R $_{A B}$ = $\frac{4 \times 5}{4 + 5} = \frac{20}{9}$