The cell in a figure below has an e.m.f. of 1.8V and negligible internal resistance. Determine: i) total resistance in a circuit. ii) the current in the circuit. iii) reading of the voltmeter

$$R_p = \frac{R_1 \times R_2}{R_1 + R_2}$$ $$R_p = \frac{2 \, \Omega \times 3 \, \Omega}{2 \, \Omega + 3 \, \Omega}$$ $$R_p = \frac{6 \, \Omega^2}{5 \, \Omega}$$ $$R_p = 1.2 \, \Omega$$

Kizuizi cha 3 Ω kimeunganishwa mfululizo na kizuizi sawa cha sambamba ($R_p$).

$$R_{total} = R_{series} + R_p$$ $$R_{total} = 3 \, \Omega + 1.2 \, \Omega$$ $$R_{total} = 4.2 \, \Omega$$

Jumla ya vizuizi kwenye mzunguko ni $\boxed{\text{4.2 } \Omega}$.

ya seli na $R$ ni jumla ya vizuizi.

$$I = \frac{V}{R_{total}}$$ $$I = \frac{1.8 \, \text{V}}{4.2 \, \Omega}$$ $$I = \frac{18}{42} \, \text{A}$$ $$I = \frac{3}{7} \, \text{A}$$ $$I \approx 0.43 \, \text{A}$$

Mkondo wa umeme kwenye mzunguko ni $\boxed{\text{0.43 A}}$.

Mkondo wa umeme unaopita kwenye kizuizi hiki ni mkondo jumla ($I$) uliopatikana hapo juu.

$$V_{voltmeter} = I \times R_{3\Omega}$$ $$V_{voltmeter} = \frac{3}{7} \, \text{A} \times 3 \, \Omega$$ $$V_{voltmeter} = \frac{9}{7} \, \text{V}$$ $$V_{voltmeter} \approx 1.29 \, \text{V}$$

Usomaji wa voltmeter ni $\boxed{\text{1.29 V}}$.