ELECTROMAGNETIC WAVES ELECTROMAGNETIC WAVES EXERCISE1 CLASS WORK ELECTROMAGNETIC

ELECTROMAGNETIC WAVES

ELECTROMAGNETIC WAVES EXERCISE-1 CLASS WORK

ELECTROMAGNETIC WAVES EXERCISE-I CLASS WORK DISPLACEMENT CURRENT displacement current 1) 0. 139 A 2) 1. 39 A 3) 13. 9 A 4) 139 A Solution:

ELECTROMAGNETIC WAVES = 13. 89 ≅ 13. 9 A KEY: 3

ELECTROMAGNETIC WAVES 2) The voltage between the plates of a parallel plate condenser of capacity 2. 0 F is charging at a rate of 10 Vs-1. The displacement current. . . 1) 2 m A 2) 2 A 3) 20 A 4) 2 A Solution:

ELECTROMAGNETIC WAVES KEY: 3

ELECTROMAGNETIC WAVES 3) A parallel condenser has conducting plates of radius 8 cm separated by a distance of 2. 0 mm. It is charged by an external source, with a constant charging current of 0. 15 A. The displacement current is…. . 1) 0. 10 A 2) 0. 15 A Solution: Id=i 3) 0. 20 A 4) 0. 30 A We know that

ELECTROMAGNETIC WAVES 4) A condenser having circular plates having radius 2 cm and separated by a distance of 3 mm. It is charged with a current of 0. 1 A. The rate at which the potential difference between the plates change is. . . 1) 9 × 1010 V / s Solution: 2) 1. 8 × 1010 V / s 3) 2. 7 × 106 V / s 4) 2. 7 × 1010 V/s i = 0. 1 A;

ELECTROMAGNETIC WAVES KEY: 4

ELECTROMAGNETIC WAVES 5) A parallel plate condenser of capacity 100 p. F is connected to 230 V of AC supply of 300 rad/ sec frequency. The rms value of displacement current. . Solution:

ELECTROMAGNETIC WAVES 6) A parallel plate capacitor of plate separation 4 mm and area of 40 cm 2 is connected to 400 V source. The value of displacement current for 10 -4 s is. . . Solution: 1) 35. 4 A 2) 3. 54 A 3) 1. 75 A 4) 0. 175 A V = 400 V;

ELECTROMAGNETIC WAVES MAGNETIC FIELD PRODUCED BETWEEN THE PLATES OF A PARALLEL PLATE CONDUCTOR 7) A condenser has two conducting plates of radius 10 cm separated by a distance of 5 mm. It is charges with a constant current of 0. 15 A. the magnetic field at a point 2 cm from the axis in the gap is. . . Solution: i = 0. 15 A; B =?

ELECTROMAGNETIC WAVES 8) The diameter of the condenser plate is 4 cm. It is charged by an external current of 0. 2 A. The maximum magnetic field induced in the gap. . . 1) 2 T 2) 4 T 3) 6 T 4) 8 T Solution: i = 0. 2 A

ELECTROMAGNETIC WAVES 9) An AC rms voltage of 2 V having a frequency of 50 KHz is applied to a condenser of capacity of 10 F. The maximum value of the magnetic field between the plates of the condenser if the radius of plate is 10 cm is. . . 1) 0. 4 T Solution: V = 2 volts; 2) 4 T 3) 4 T i= V�� C 4) 40 T i= 2× 2�� n×C = 2��

ELECTROMAGNETIC WAVES KEY: 2

ELECTROMAGNETIC WAVES 10) The graph representing the variation of induced magnetic field in the gap of the condenser plates during its charging with the distance from the axis of the gap is. . B B 1) 3) 2) distance 4) B B distance Solution: distance

ELECTROMAGNETIC WAVES 11) The magnetic field between the plates of radius 12 cm separated by distance of 4 mm of a parallel plate capacitor of capacitance 100 p. F. Along the axis of plates having conduction of 0. 15 A is. . 1) zero 2) 1. 5 T Solution: 3) 15 T 4) 0. 15 T B=0 In between the plates the magnetic field due to the conduction current is zero

ELECTROMAGNETIC WAVES Solution:

ELECTROMAGNETIC WAVES KEY: 1

ELECTROMAGNETIC WAVES WAVE EQUATION 13) The all India radio station at Vijayawada transmits signals at 840 k. C/s. The length of the radio wave is. . . 1) 35. 7 m 2) 357 m 3) 35. 7 km 4) 3. 57 m Solution: =? C = n

ELECTROMAGNETIC WAVES 14) The velocity of an electromagnetic wave in a medium is 2 × 108 ms-1. If the relative permeability is 1 the relative permittivity of the medium is ( c 0 = 3 × 108 ms-1). . . 1) 2. 25 Solution: 2) 1. 5 3) 4/9 4) 2/3

ELECTROMAGNETIC WAVES KEY: 1

ELECTROMAGNETIC WAVES Solution:

ELECTROMAGNETIC WAVES RELATION BETWEEN B & E ^ ^ 1) 4. 2 × 10 -8 k T ^ 2) 2. 1 × 10 -8 k T 3) 18. 9 × 108 ^ k. T ^ 4) 2. 1 × 10 -8 k T Solution:

ELECTROMAGNETIC WAVES Solution:

ELECTROMAGNETIC WAVES 18) In an apparatus, the electric field was found to oscillate with amplitude of 18 V/m. The amplitude of the oscillating magnetic field will be. . . Solution: 1) 4 × 10 -6 T 2) 6 × 10 -8 T 3) 9 × 10 -9 T 4) 11 × 10 -11 T B =?

ELECTROMAGNETIC WAVES MOMENTUM AND FORCE 19) Light with an energy flux of 18 W/cm 2 falls on a non-reflecting surface of 20 cm 2 at normal incidence the momentum delivered in 30 minutes is …. . Solution:

ELECTROMAGNETIC WAVES time =30 min = 1800 sec KEY: 2

ELECTROMAGNETIC WAVES Solution: Force =? time =1 min = 60 sec Momentum = ?

ELECTROMAGNETIC WAVES KEY: 1

ELECTROMAGNETIC WAVES Solution: 1) 1. 2 × 10 -6 N 2) 2. 4 × 10 -6 N 3) 2. 16 × 10 -3 N 4) 1. 5 × 10 -6 N time =30 min = 1800 sec

ELECTROMAGNETIC WAVES KEY: 1

ELECTROMAGNETIC WAVES 22) Light with an energy flux 36 W/cm 2 is incident on a well polished metal square plate of side 2 cm. The force experienced by it is. . . 1) 0. 96 N Solution: 2) 0. 24 N 3) 0. 12 N 4) 0. 36 N

ELECTROMAGNETIC WAVES 23) In an electromagnetic wave, the amplitude of electric field is 1 V/m. The frequency of wave is 5 × 1014 Hz. The wave is propagating along z-axis. The average energy density of electric field, in joule/m 3, will be. . . 2) 2. 2 × 10 -12 3) 3. 3 × 10 -13 4) 4. 4 × 10 -14 1) 1. 1 × 10 -11 Solution:

ELECTROMAGNETIC WAVES 24) The rms values of the electric filed of a plane electromagnetic wave is 314 V/m. The average energy density of electric field and the average energy density are. . .

ELECTROMAGNETIC WAVES Solution:

ELECTROMAGNETIC WAVES

ELECTROMAGNETIC WAVES KEY: 2

ELECTROMAGNETIC WAVES 25) In an electromagnetic wave the electric and magnetizing fields are 100 Vm-1 and 0. 265 Am-1. The maximum rate of energy flow per unit area is. . . 1) 26. 5 Wm-2 2) 36. 5 Wm-2 Solution: 3) 46. 7 Wm-2 4) 765 Wm-2

ELECTROMAGNETIC WAVES INTENSITY: Solution: C = n

ELECTROMAGNETIC WAVES KEY: 1

ELECTROMAGNETIC WAVES 27) The sun delivers 103 W/m 2 of electromagnetic flux incident on a roof of dimensions 8 m × 20 m, will be. . . 1) 6. 4 × 103 W Soluti on: 2) 3. 4 × 104 W 3) 1. 6 × 105 W The power of radiation P = flux × area 4) 3. 2 × 105 W

ELECTROMAGNETIC WAVES Thank you…