AMIE Study Circle Blog

1. A wedge is described by z = 0, 30° < ⲫ < 60°. Which of the following is incorrect? (a) The wedge lies in the x - y plane. (b) It is infinitely long. (c) On the wedge, 0 < ρ < ∞ (d) A unit normal to the w edge is ± a z (c) The wedge includes neither the x-axis nor the y-axis. 2. Given fie ld A̅ = 3x 2 yza̅ x  + x 3 za̅ y  + (x 3 y - 2z)a̅ z  it can be sa id th at A̅  is. (a) Harmonic (b) Divergenceless (c) Solenoidal (d) Conservative 3. If ∇ .D̅ = ∈ ∇ .E̅ and ∇ ∇ .J̅ = σ ∇ .E̅  in a given material, the material is said to be (a) Isotropic (b) L inear (c) Homogenous (d) Linear and homogenous. 4. One of these equations is not Maxwell’s equation for a static electromagnetic field in a linear ho mogeneous medium. (a)  ∇ 2 A̅ = μ 0 J̅ (b) ∇ .B̅ = 0 (c) ∇  x D̅ = 0 (d) ∮B̅.dl̅ = μ 0 I̅ 5. When a sinusoidal voltage is suddenly applied to an electrical circuit which of the following constitutes its response? (a) St...

Answer the following in brief What are complex frequency and real frequency? Give their applications. A type of frequency that depends on two parameters; one is the σ which controls the magnitude of the signal and the other is “w”, which controls the rotation of the signal; is known as “complex frequency”. s = σ + jw "s" is a generalized frequency variable whose real part a describes growth and decay of the amplitudes of signals, and whose imaginary part jω is the angular frequency in the usual sense. From the pole-zero diagram of a network function, how can you understand whether the network is stable or not? Given a polynomial N(s) = P(s) / Q(s) By factorizing the numerator and denominator polynomials, we can easily show that the polynomial becomes zero when the ‘s’ terms in the numerator polynomial have the values s=0, -z₁,-z₂…….-zₙ, thus the roots of numerator define the zeros. Also, the roots of the denominator polynomial define the poles of the function. Zeros are marke...

1. A voltage waveform V (t) =12t² is applied across a 1 H inductor for t ≥ 0, with the initial electric current through it is zero. The electric current through inductor for t ≥ 0 is given by (a) 12t (b) 24t (c) 12t² (d) 4t³  2. In the network shown, what is the electric current I in the direction shown (a) 0 A (b) (1/3) A (c) (5/6) A (d) 4 A 3. Which of the following cannot be connected in series unless they are identical? (a) Voltage source  (b) Current source  (c) Both (d) Resistance 4. A system with transfer function G(s) = [(s² + 9)(s + 2)]/[(s + 1)(s + 3)(s + 4)] is exited by sinωt. The steady state output of the system is zero at (a) Q = 1 rad/sec (d) Q = 2 rad/sec (c)  Q  = 3 rad/sec (d) Q = 4 rad/sec 5. F or static magnetic field, Maxwell’s curl equation is given by (a) ∇.B̅ = μ 0 .J̅ (b) ∇.B̅ = 0 (c) ∇xB̅ = μ 0 .J̅ (d) ∇xB̅ = μ 0/ J̅ 6. Which of the following laws of electromagnetic theory is associated with force experienced ...

Answer the following in the brief. Define half-power frequencies in resonant RLC series circuit If the series RLC circuit is driven by a variable frequency at a constant voltage, then the magnitude of the current, I is proportional to the impedance, Z, therefore at resonance the power absorbed by the circuit must be at its maximum value as P = I²Z. If we now reduce or increase the frequency until the average power absorbed by the resistor in the series resonance circuit is half that of its maximum value at resonance, we produce two frequency points called the half-power points which are -3dB down from maximum, taking 0dB as the maximum current reference. Th e point corresponding to the lower frequency at half the power is called the “ lower cut-off frequency ”, labelled f L  with the point corresponding to the upper frequency at half power being called the “ upper cut-off frequency ”, labelled f H . The distance between these two points, i.e. ( f H  –  f L ...

Explain the following in brief Superposition theorem Superposition theorem states that in any linear, bilateral network where more than one source is present, the response across any element in the circuit, is the sum of the responses obtained from each source considered separately while all other sources are replaced by their internal resistance. Superposition theorem is a circuit analysis theorem that is used to solve the network where two or more sources are present and connected. The application of this theorem is both the AC & DC circuits where it assists to build the circuits like “Norton” as well as “Thevenin” equivalent circuits. See example and circuit diagram Norton’s theorem Norton’s Theorem states that it is possible to simplify any linear circuit, no matter how complex, to an equivalent circuit with just a single current source and parallel resistance connected to a load.  See example with a diagram Coulomb’s law Coulomb’s Law.  Coulomb stated that the fo...

Explain the following terms in brief Final Value theorem In the solution of Networks, Transient, and Systems sometimes we may not be interested in finding out the entire function of time f(t) from its Laplace Transform F(s), which is available for the solution. It is very interesting to find that we can find the first value or last value of f(t) or its derivatives without having to find out the entire function f(t). If F(s) is given, we would like to know what is F(∞), Without knowing the function f(t), which is Inverse Laplace Transformation, at time t→ ∞. This can be done by using the property of Laplace Transform known as the Final Value Theorem. The final value theorem and initial value theorem are together called the Limiting Theorems. If f(t) and f'(t) both are Laplace Transformable and sF(s) has no pole in jw axis and in the R.H.P. (Right half Plane) then, Tellegen theorem According to the Tellegen theorem, the summation of instantaneous powers for the n number of branches i...

Explain the following terms in brief Superposition theorem with a suitable circuit diagram. Superposition theorem states that in any linear, bilateral network where more than one source is present, the response across any element in the circuit, is the sum of the responses obtained from each source considered separately while all other sources are replaced by their internal resistance. Superposition theorem is a circuit analysis theorem that is used to solve the network where two or more sources are present and connected. The application of this theorem is both the AC & DC circuits where it assists to build the circuits like “Norton” as well as “Thevenin” equivalent circuits. See example and circuit diagram Norton’s theorem with a suitable circuit diagram. Norton’s Theorem states that it is possible to simplify any linear circuit, no matter how complex, to an equivalent circuit with just a single current source and parallel resistance connected to a load.      Coulomb...