JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II ELECTRICAL ENGINEERING Previous Question Paper (November/December - 2020 - R16)

Consider a conductor of length l carrying a current I placed in a uniform magnetic field of flux density B. When a charge q moves through the conductor with a drift velocity v, it experiences a Lorentz force given by F = q(v × B). For a small element of length dl, the charge dq passing through it in time dt is dq = I dt. Since the drift velocity is v = dl/dt, we can write dq v = I dl. Substituting this into the force equation, the force on the element is dF = I(dl × B). Integrating over the entire length of the conductor, the total force is F = I(l × B). In magnitude, this is expressed as F = BIl sin(θ), where θ is the angle between the conductor and the magnetic field lines.

To find the equivalent resistance between terminals X and Y, identify the series and parallel combinations within the circuit. First, simplify any resistors connected in series by summing their values (R_eq = R₁ + R₂ + ...). Next, simplify parallel branches using the formula 1/R_eq = 1/R₁ + 1/R₂ + ... or R_eq = (R₁ × R₂) / (R₁ + R₂) for two resistors. Continue this reduction process step-by-step, redrawing the circuit after each simplification, until only a single equivalent resistance remains between terminals X and Y.