(2) Explain Continuity Equation
(3) Describe the boundary condition between free space and conductor. What is an
importance of boundary condition?
(4) Describe the boundary condition between free space and perfect dielectric material.
(5) What is capacitance? Derive the equation for capacitance of a parallel plate capacitor of
area S m2 and a separation of d meter.
‘The divergence of the curl of a vector is zero’-Justify the statement with one example.
Find the ay dot aɸ and ax dot aθ
Given 60 μC point charge located at the origin, find the total electric flux passing through that portion of the sphere r=26 cm bounded by 0˂θ˂π/2 and 0˂ɸ˂π/2.
For a coaxial cable find the electric field density inside the inner core, in between inner and outer core and outside the cable.
(b) Answer the following
What is Gradient? with help of gradient prove that E= – V
Find the volume charge density that is associated with D = ρz2 sin2ɸ ap + ρz2 sinɸcosɸ aɸ + ρ2z sin2ɸ az c/m2
Q.2 (a) Derive the electric field intensity and electric field density due to an infinite and uniform line charge density.
(b) In the space, a line charge ρL=80 nC/m lies along the entire Z-axis, while point charge of 100 nC each are located at (1,0,0) and (0,1,0). Find the potential difference VPQ given P (2,1,0) and Q (3,2,5).
(b) Given the flux density D = (2cosθ/r3) ar + (sinθ/r3) aθ c/m2, evaluate both sides of the divergence theorem for the region defined by 1˂ r ˂ 2 , 0 ˂ θ ˂ π/2 , 0˂ ɸ˂ π/2
Q.3 (a) Describe the boundary condition between free space and conductor. What is an importance of boundary condition?
(b) Write Maxwell’s equations in point form and explain physical significance of equations.
Q.3 (a) Derive Poisson’s and Laplace’s equations and states their applications.
(b) Write Maxwell’s equations in integral form and explain their physical significance.
Q.4 (a) State and explain Ampere’s circuital law. Find the magnetic field intensity due to long straight conductor using Ampere’s circuital law.
(b) A charge of 10 nC is moving with a velocity of 107(-0.5 ax + ay -0.71 az) m/s. Determine the force exerted on the test charge when
a magnetic induction B = ( ax + 2ay + 3 az) mWb/m2 is applied
an electric field E = (3ax + 2ay + az) kV/m is applied.
When B and E given above are applied simultaneously.
Q.4 (a) What is curl? With help of curl meter explain the physical interpretation of curl and state its applications.
(b) A filamentary current of 10 A is directed in from infinity to the origin on the positive x axis, and then back to infinity along the positive y axis. Use the Biot- Savart law to find H at P (0,0,1)
Q.5 (a) Define and explain the following terms:
Skin effect and
Standing wave ratio
(b) Write short note on:
Wave motion in free space
Magnetic boundary condition
Q.5 (a) Define and explain the following terms:
The scalar and Vector magnetic potential
(b) (i) Transform the 5ax vector to spherical coordinate at A(x = 2,y = 3, z = -1).
(ii) Given V = (10/r2 ) sinθcosɸ, Find the electric flux density at (2, π/2,0)
(b) A power station has following daily load cycle:Time(hrs) Load(MW)0-6 20
Draw load curve .Also calculate:
OR(b) Calculate volume of conductor material used in
Overhead system, with 3wire dc system
Underground system, with 3 phase 3wire system
Q.3 (a) Explain string efficiency and methods of improving it.Answer Link
(b) Explain corona with advantages and disadvantages of it. Also define:
Critical disruptive corona voltage.
Visual corona voltage.
ORQ.3 (a) Explain FACTS devices.
(b) Explain different equipments used in substations with its symbols.
Q.4 (a) Define underground cables, draw and explain internal construction of it.
(b) A transmission line has a span of 100m between level supports. The conductor has cross-section area of 5cm2. The tension is the conductor is 2500 kg. If specific gravity of conductor material is 9.98m /cm3 and wind pressure is 1.2 kg/m. Calculate sag and vertical sag.
ORQ.4 (a) A part of transposition cycle of 3phase double circuit line is shown below. Radius of each conductor is 0.9cm.The conductors are made up of solid copper. Find the inductance/phase/km of the line.[image]
(b) Explain following in respect to medium transmission line.
• Nominal T method
• Nominal π method
Q.5 (a) Draw and explain following distribution schemes:
Secondary AC distribution system
Radial distribution system
Ring main distribution system
(b) Explain importance of voltage control and method to achieve it.
ORQ.5 (a) Differentiate most economical p.f. and most ideal p.f
(c) A two conductor street mains AB, 500 m in length is fed from both ends at 250 V. Loads 50 A, 60 A,40 A and 30 A are tapped at distance of 100 m, 250 m, 350 m, and 400 m from A respectively. If cross section area of the conductors be 1 cm2 and specific resistance of conductors is 1.7 × 10 -8 Ωm. Determine minimum consumer voltage.