Electromagnetic waves-MCQ-Advance

Electromagnetic waves-MCQ-Advance

Dear Readers,

Physics is an important subject in preparation for various Competitive exams.To keep a track of your preparation we have designed a small quiz of 10 Advance Level Questions on Electromagnetic waves. You have 10 minutes to solve the quiz, click the start timer button in order to start the timer and then click on submit button at the end to submit the quiz and view your scores and correct answers.

Q1. A parallel plate capacitor of plate separation 2 mm is connected in an electric circuit having source voltage 400 V. if the plate area is 60 cm ² , then the value of displacement current for 10 ^{− 6} sec will be

•  1.062 amp
•  1.062 x 10 ^-2 amp
•  1.062 x 10 ^-3 amp
•  1.062 x 10 ^-4 amp

1.062 x 10 ^-4 amp

Q2. In an electromagnetic wave, the amplitude of electric field is 1 V/m. the frequency of wave is 5 x 10 ¹⁴ Hz . The wave is propagating along z-axis. The average energy density of electric field, in Joule/m ³ , will be

•  1 . 1 x 10 ^{− 11}
•  2 . 2 x 10 ^{− 12}
•  3 . 3 x 10 ^{− 13}
•  4 . 4 x 10 ^{− 14}

2 . 2 x 10 ^{− 12}

Q3. To establish an instantaneous displacement current of 2 A in the space between two parallel plates of 1 µ F capacitor, the potential difference across the capacitor plates will have to be changed at the rate of

•  4 x 10 ⁴ V / s
•  4 x 10 ⁶ V / s
•  2 x 10 ⁴ V / s
•  2 x 10 ⁶ V / s

2 x 10 ⁶ V / s

Q4. A laser beam can be focussed on an area equal to the square of its wavelength A He-Ne laser radiates energy at the rate of 1 mW and its wavelength is 632.8 nm. The intensity of focussed beam will be

•  1 . 5 x 10 ¹³ W / m ²
•  2 . 5 x 10 ⁹ W / m ²
•  3 . 5 x 10 ¹⁷ W / m ²
•  9 . 5 x 10 ¹³ W / m ²

2 . 5 x 10 ⁹ W / m ²

Q5. An electric field of 300 V/m is confined to a circular area 10 cm in diameter. If the field is increasing at the rate of 20 V/m-s, the magnitude of magnetic field at a point 15 cm from the centre of the circle will be

•  1 . 85 x 10 ^{− 15} T
•  1 . 85 x 10 ^{− 16} T
•  1 . 85 x 10 ^{− 17} T
•  1 . 85 x 10 ^{− 18} T

1 . 85 x 10 ^{− 18} T

Q6. A lamp emits monochromatic green light uniformly in an directions. The lamp is 3% efficient in converting electrical power to electromagnetic waves and consumes 100 W of power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of 10 m from the lamp will be

•  1.34 V/m
•  2.68 V/m
•  5.36 V/m
•  9.37 V/m

1.34 V/m

Q7. A point source of electromagnetic radiation has an average power output of 800 W. The maximum value of electric field at a distance 4.0 m from the source is

•  64.7 V/m
•  57.8 V/m
•  56.72 V/m
•  54.77 V/m

54.77 V/m

Q8. The wave impedance of free space is

•  Zero
•  376.6 Ω
•  33.6 Ω
•  3.76 Ω

376.6 Ω

Q9. The transmitting antenna of a radio-station is mounted vertically. At a point 10 km due north of the transmitter the peak electric field is 10 ^{− 3} Vm ^{− 1} . The magnitude of the radiated magnetic field is

•  3 . 33 x 10 ^{− 10} T
•  3 . 33 x 10 ^{− 12} T
•  10 ^{− 3} T
•  3 x 10 ⁵ T

3 . 33 x 10 ^{− 12} T

Q10. A wave is propagating in a medium of electric dielectric constant 2 and relative magnetic permeability 50. The wave impedance of such a medium is

•  5 Ω
•  376.6 Ω
•  1833 Ω
•  3776 Ω

1833 Ω