Question

intr un atelier ard cate 5 ore , 3 becuri cu puterea nominala de 100w , fiecare la o tensiune de 220V. STIIND ca becurile sunt conectate in paralel. calculati:
a) intensitatea curentului prin fiecare bec
b) rezistenta unui bec
c) energia totala intr o zi​

Answer 1

a)

$\displaystyle \\P_1 = U \times I_1 \rightarrow I_1 = \frac{P_1}{U} = \frac{100}{220} = 0,45 \ A$

$\displaystyle \\I_1 = I_2 = I_3 = 0,45 \ A$

b)

$\displaystyle \\I_1 = \frac{U}{B_1} \rightarrow B_1 = \frac{U}{I_1} \\ \\B_1 = \frac{220}{ \frac{100}{220}} = \frac{220*220}{100} = 484 \ ohm$

c)

$\displaystyle \\R_{total} = \frac{B_1}{3} = \frac{484}{3} = 161,33 \ ohm \\ \\I = I_1 + I_2 + I_3 = 1,36 \ A \\ \\\Delta t = 5 \ h = 5 * 3600 = 18.000 \ s \\ \\W = I^2 * R_{total} * \Delta t \\ \\W = 1,36^2 * 161,33 * 18.000 \\ \\W = 5371,12 \ kJ$