Combination of Cells in Series and in Parallel

Two metallic wires, P₁ and P₂ of the same material and same length but different cross-sectional areas, A₁ and A₂ are joined together and connected to a source of emf. Find the ratio of the drift velocities of free electrons in the two wires when they are connected (i) in series, and (ii) in parallel.

Two cells of emfs E₁ and E₂ and internal resistances r₁ and r₂ respectively are connected in parallel as shown in the figure. Deduce the expression for the

1. equivalent emf of the combination
2. equivalent internal resistance of the combination
3. potential difference between the points A and B.

Two cells of emf E₁ and E₂ and internal resistances r₁ and r₂ are connected in parallel, with their terminals of the same polarity connected together. Obtain an expression for the equivalent emf of the combination.

Two cells of emf’s approximately 5V and 10V are to be accurately compared using a potentiometer of length 400 cm.

A 60 Ω resistor, a 1.0 H inductor and a 4 μF capacitor are connected in series to an ac supply generating an emf e = 300 sin (500t) V. Calculate:

1. impedance of the circuit.
2. peak value of the current flowing through the circuit.
3. phase difference between the current and the supply voltage.

Calculate force per unit length acting on the wire B due to the current flowing in the wire A.(See
Figure 2 below)

Give reason/short answer.

In the given circuit diagram two resistors are connected to a 5V supply.

A third resistor is now connected in parallel with 6Ω resistor. Will the potential difference across the 8Ω resistor the larger, smaller, or the same as before? Explain the reason for your answer.

The equivalent resistance of series combination of two resistors is 's'. When they are connected in parallel, the equivalent resistance is 'p'. If s = np, then the minimum value for n is ______. (Round off to the Nearest Integer)