Set No. 2 II B.Tech I Semester Examinations,May 2011 ELECTROMAGNETIC FIELDS Electrical And Electronics Engineering Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks 1. (a) A co axial cable with inner and outer conductor radii a and b respectively have the respective voltage Va and Vb. By using Laplace equation, find E at all points. [10] (b) The construction of a paper capacitor is as follows: Aluminum foil of 100 cm 2 area is placed on both sides of paper of thickness 0.03 mm. If the dielectric constant of paper is given as 3, and its dielectric breakdown strength is 200 kv/cm, what is the rating of the capacitor? [6] 2. (a) Derive.D = ρ v from fundamentals. [8] (b) Four point charges of Q, -2Q, 3Q and 4Q are located at the corners of a square of side d. find E at center of the square. [8] 3. Derive an expression for energy density in a magnetic field and use this formula for computing energy density in a magnetic field having flux density equal to 1 Tesla. [16] 4. (a) Find an expression for the magnetic flux density at the centre of a circular current loop of radius R m and carrying a current of I amp. [10] (b) What is the flux density at the centre of square loop of 10 turns carrying current of 10 amps? The loop is in air and is 2 meters on a side. [6] 5. (a) State and prove the conditions at the boundary between two dielectrics. [10] (b) Determine the expression for the insulation resistance of a co-axial cable of length L and inner and outer radii of a and b respectively. [6] 6. (a) Show that the intensity of electric field at any point inside a hollow charged spherical conductor is zero. [6] (b) A sphere of radius a has the charge distribution ρ(r) C/m 3 which produces an electric field intensity given by, E r = A r 4, for r a, = Ar 2, for r> Where A is a constant. Find the corresponding charge distribution ρ(r). [10] 7. A square loop of wire 25 cm by 25 cm has a voltmeter (of infinite impedance) connected in series with one side. Determine the voltage induced by the meter when the loop is placed in an alternating field, the maximum intensity of which is 1 AMP per metre. The plane of the loop is perpendicular to the magnetic field varying at a frequency of 10 MHz. [16] 1
Set No. 2 8. A single-phase circuit comprises two parallel conductors A and B, each 1 cm diameter and spaced 1 m apart. The conductors carry current of +100 and -100 Amps. respectively. Determine the filed intensity at the surface of each conductor and also in space exactly midway between A and B. [16] 2
Set No. 4 II B.Tech I Semester Examinations,May 2011 ELECTROMAGNETIC FIELDS Electrical And Electronics Engineering Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks 1. (a) Find an expression for the magnetic flux density at the centre of a circular current loop of radius R m and carrying a current of I amp. [10] (b) What is the flux density at the centre of square loop of 10 turns carrying current of 10 amps? The loop is in air and is 2 meters on a side. [6] 2. A square loop of wire 25 cm by 25 cm has a voltmeter (of infinite impedance) connected in series with one side. Determine the voltage induced by the meter when the loop is placed in an alternating field, the maximum intensity of which is 1 AMP per metre. The plane of the loop is perpendicular to the magnetic field varying at a frequency of 10 MHz. [16] 3. Derive an expression for energy density in a magnetic field and use this formula for computing energy density in a magnetic field having flux density equal to 1 Tesla. [16] 4. (a) A co axial cable with inner and outer conductor radii a and b respectively have the respective voltage Va and Vb. By using Laplace equation, find E at all points. [10] (b) The construction of a paper capacitor is as follows: Aluminum foil of 100 cm 2 area is placed on both sides of paper of thickness 0.03 mm. If the dielectric constant of paper is given as 3, and its dielectric breakdown strength is 200 kv/cm, what is the rating of the capacitor? [6] 5. (a) Derive.D = ρ v from fundamentals. [8] (b) Four point charges of Q, -2Q, 3Q and 4Q are located at the corners of a square of side d. find E at center of the square. [8] 6. (a) Show that the intensity of electric field at any point inside a hollow charged spherical conductor is zero. [6] (b) A sphere of radius a has the charge distribution ρ(r) C/m 3 which produces an electric field intensity given by, E r = A r 4, for r a, = Ar 2, for r> Where A is a constant. Find the corresponding charge distribution ρ(r). [10] 7. (a) State and prove the conditions at the boundary between two dielectrics. [10] (b) Determine the expression for the insulation resistance of a co-axial cable of length L and inner and outer radii of a and b respectively. [6] 3
Set No. 4 8. A single-phase circuit comprises two parallel conductors A and B, each 1 cm diameter and spaced 1 m apart. The conductors carry current of +100 and -100 Amps. respectively. Determine the filed intensity at the surface of each conductor and also in space exactly midway between A and B. [16] 4
Set No. 1 II B.Tech I Semester Examinations,May 2011 ELECTROMAGNETIC FIELDS Electrical And Electronics Engineering Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks 1. (a) Show that the intensity of electric field at any point inside a hollow charged spherical conductor is zero. [6] (b) A sphere of radius a has the charge distribution ρ(r) C/m 3 which produces an electric field intensity given by, E r = A r 4, for r a, = Ar 2, for r> Where A is a constant. Find the corresponding charge distribution ρ(r). [10] 2. A square loop of wire 25 cm by 25 cm has a voltmeter (of infinite impedance) connected in series with one side. Determine the voltage induced by the meter when the loop is placed in an alternating field, the maximum intensity of which is 1 AMP per metre. The plane of the loop is perpendicular to the magnetic field varying at a frequency of 10 MHz. [16] 3. A single-phase circuit comprises two parallel conductors A and B, each 1 cm diameter and spaced 1 m apart. The conductors carry current of +100 and -100 Amps. respectively. Determine the filed intensity at the surface of each conductor and also in space exactly midway between A and B. [16] 4. Derive an expression for energy density in a magnetic field and use this formula for computing energy density in a magnetic field having flux density equal to 1 Tesla. [16] 5. (a) A co axial cable with inner and outer conductor radii a and b respectively have the respective voltage Va and Vb. By using Laplace equation, find E at all points. [10] (b) The construction of a paper capacitor is as follows: Aluminum foil of 100 cm 2 area is placed on both sides of paper of thickness 0.03 mm. If the dielectric constant of paper is given as 3, and its dielectric breakdown strength is 200 kv/cm, what is the rating of the capacitor? [6] 6. (a) State and prove the conditions at the boundary between two dielectrics. [10] (b) Determine the expression for the insulation resistance of a co-axial cable of length L and inner and outer radii of a and b respectively. [6] 7. (a) Find an expression for the magnetic flux density at the centre of a circular current loop of radius R m and carrying a current of I amp. [10] (b) What is the flux density at the centre of square loop of 10 turns carrying current of 10 amps? The loop is in air and is 2 meters on a side. [6] 5
Set No. 1 8. (a) Derive.D = ρ v from fundamentals. [8] (b) Four point charges of Q, -2Q, 3Q and 4Q are located at the corners of a square of side d. find E at center of the square. [8] 6
Set No. 3 II B.Tech I Semester Examinations,May 2011 ELECTROMAGNETIC FIELDS Electrical And Electronics Engineering Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks 1. Derive an expression for energy density in a magnetic field and use this formula for computing energy density in a magnetic field having flux density equal to 1 Tesla. [16] 2. (a) State and prove the conditions at the boundary between two dielectrics. [10] (b) Determine the expression for the insulation resistance of a co-axial cable of length L and inner and outer radii of a and b respectively. [6] 3. (a) Find an expression for the magnetic flux density at the centre of a circular current loop of radius R m and carrying a current of I amp. [10] (b) What is the flux density at the centre of square loop of 10 turns carrying current of 10 amps? The loop is in air and is 2 meters on a side. [6] 4. A single-phase circuit comprises two parallel conductors A and B, each 1 cm diameter and spaced 1 m apart. The conductors carry current of +100 and -100 Amps. respectively. Determine the filed intensity at the surface of each conductor and also in space exactly midway between A and B. [16] 5. (a) A co axial cable with inner and outer conductor radii a and b respectively have the respective voltage Va and Vb. By using Laplace equation, find E at all points. [10] (b) The construction of a paper capacitor is as follows: Aluminum foil of 100 cm 2 area is placed on both sides of paper of thickness 0.03 mm. If the dielectric constant of paper is given as 3, and its dielectric breakdown strength is 200 kv/cm, what is the rating of the capacitor? [6] 6. (a) Show that the intensity of electric field at any point inside a hollow charged spherical conductor is zero. [6] (b) A sphere of radius a has the charge distribution ρ(r) C/m 3 which produces an electric field intensity given by, E r = A r 4, for r a, = Ar 2, for r> Where A is a constant. Find the corresponding charge distribution ρ(r). [10] 7. A square loop of wire 25 cm by 25 cm has a voltmeter (of infinite impedance) connected in series with one side. Determine the voltage induced by the meter when the loop is placed in an alternating field, the maximum intensity of which is 1 AMP per metre. The plane of the loop is perpendicular to the magnetic field varying at a frequency of 10 MHz. [16] 7
Set No. 3 8. (a) Derive.D = ρ v from fundamentals. [8] (b) Four point charges of Q, -2Q, 3Q and 4Q are located at the corners of a square of side d. find E at center of the square. [8] 8