R4RIN.com – MCQs, Mock Tests | CBES Board Class 12 CBES Board(Class 12-Physics)MCQ Questions with Answers(Chapter 8 Electromagnetic Waves)

1. Maxwell in his famous equations of electromagnetism introduced the concept of
ac current
displacement current
impedance
reactance

2. The conduction current is same as displacement current when source is
ac only
dc only
either ac or dc
neither dc nor ac

3. If a variable frequency ac source is connected to a capacitor then with decrease in frequency the displacement current will
increase
decrease
remains constant
first decrease then increase

4. An electromagnetic wave can be produced, when charge is
moving with a constant velocity
moving in a circular orbit
falling in an electric field
both (2) and (3)

5. Which of the following statement is false for the properties of electromagnetic waves?
Both electric and magnetic field vectors attain the maxima and minima at the same place and same time.
The energy in electromagnetic waves is divided equally between electric and magnetic field vectors.
Both electric and magnetic field vectors are parallel to each other and perpendicular to the direction of propagation of wave.
These waves do not require any material medium for propagation.

6. Which of the following has/have zero average value in a plane electromagnetic wave?
Both magnetic and electric fields
Electric field only
Magnetic field only
None of these

7. The ultra high frequency band of radio waves in electromagnetic wave is used as in
television waves
cellular phone communication
commercial FM radio
both (1) and (2)

8. The waves used by artificial satellites for communication is
microwaves
infrared waves
radio waves
X-rays

9. Which of the following electromagnetic waves is used in medicine to destroy cancer cells?
IR-rays
Visible rays
Gamma rays
Ultraviolet rays