Notifications
Clear all
Electricity
1
Posts
2
Users
0
Likes
233
Views
0
18/07/2021 1:02 pm
Topic starter
Three resistors are connected as shown in the diagram.
Through the resistor 5 ohm, a current of 1 ampere is flowing:
(i) What is the current through the other two resistors?
(ii) What is the p.d. across AB and across AC?
(iii) What is the total resistance?
(iii) What is the total resistance?
1 Answer
0
18/07/2021 1:19 pm
According to the diagram,
(i) Total current I = 1 amp is entering the parallel combination of R1 and R2. Let I1 current flow through R1 and I2 current flow through R2.
Then
\(I_1 = \frac{IR_2}{R_1 + R_2}\)
= \(\frac{1 \times 15}{10 + 15}\)
= 0.6 A
\(I_2 \frac{IR_1}{R_1 + R_2}\)
= \(\frac{1 \times 10}{10 + 15}\)
= 0.4 A
(ii) p.d. across AB = IR = 1 x 5 = 5V
Equivalent resistance between B and C is
\(\frac{1}{R'}\) = \(\frac{1}{R_1}\) + \(\frac{1}{R_2}\)
= \(\frac{1}{10}\) + \(\frac{1}{15}\)
\(\frac{1}{R'}\) = \(\frac{5}{30}\)
R' = 6 ohm
Total resistance between A and C is R = 5 + 6
= 11 ohm
p.d across AC = IR = 1 x 11
= 11 V
(iii) Total resistance = R3 + R'
= 5 + 6
= 11 ohm