(a)
Find the current through the emf device and each resistor in circuit 1.
(a)
Answer to Problem 39PQ
The current through the Emf device and each resistor in circuit 1 is
Explanation of Solution
According to Kirchhoff’s junction rule, in any junction, the sum of the all the currents entering the junction equals the sum of all the currents exiting the junction.
Redraw the circuit 1 and labeled it as given below
In parallel circuit, voltage across all three resistors is same that means potential difference between node A and node B is same (
According to Ohm’s law,
Here,
Rearrange the equation (I) in terms of total current
Write the expression for equivalent resistance as.
Rearrange the above expression.
Write the expression for current
Here,
Write the expression for current
Here,
Write the expression for current
Here,
Conclusion:
Substitute
Substitute
Substitute
Thus, the current in circuit 1 is
Substitute
Substitute
Substitute
Thus, the current through the Emf device and each resistor in circuit 1 is
(b)
Find the current through the emf device and each resistor in circuit 2 refer to figure P29.28.
(b)
Answer to Problem 39PQ
The current through the Emf device and each resistor in circuit 2 is
Explanation of Solution
According to Kirchhoff’s junction rule, in any junction, the sum of the all the currents entering the junction equals the sum of all the currents exiting the junction.
Redraw the circuit 2 and labeled it as given below.
In parallel circuit 2, voltage across all three resistors is same that means potential difference between node a and node b, node c & node d and node e & node f are same
Write the expression for current
Here,
Write the expression for current
Here,
Write the expression for current
Here,
Conclusion:
Substitute
Substitute
Substitute
Thus, the current in circuit 1 is
Substitute
Substitute
Substitute
Thus, the current for the given circuit resistance is
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Chapter 29 Solutions
Physics for Scientists and Engineers: Foundations and Connections
- Three resistors with resistances R1 = R/2 and R2 = R3 = R are connected as shown, and a potential difference of 225 V is applied across terminals a and b (Fig. P29.49). a. If the resistor R1 dissipates 75.0 W of power, what is the value of R? b. What is the total power supplied to the circuit by the emf? c. What is the potential difference across each of the three resistors?arrow_forwardTwo circuits made up of identical ideal emf devices ( = 1.67 V) and resistors (R = 35.9 ) are shown in Figure P29.8. What is the potential difference Vb Va a. for circuit 1 and b. for circuit 2? What is the current in the resistor c. in circuit 1 and d. in circuit 2?arrow_forwardIn Figure P29.81, N real batteries, each with an emf and internal resistance r, are connected in a closed ring. A resistor R can be connected across any two points of this ring, causing there to be n real batteries in one branch and N n resistors in the other branch. Find an expression for the current through the resistor R in this case.arrow_forward
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