Electromagnetic Waves MCQ for ISC Class-12 Physics

Electromagnetic Waves MCQ for ISC Class-12 Physics . These MCQ  / Objective Type Questions is based on latest reduced syllabus according 2021-22 session on bifurcated pattern. Main motto of Electromagnetic Waves MCQ Type Question is cracking the next upcoming exam of council. Visit official website CISCE for detail information about ISC Board Class-12 Physics.

MCQ Type Questions for ISC Physics Class-12 Electromagnetic Waves

Board	ISC
Class	12th (XII)
Subject	Physics
Ch-Name	Electromagnetic Waves
Syllabus	on bifurcated syllabus (after reduction)
Session	2021-22
Topic	MCQ / Objective Type Question

 Electromagnetic Waves MCQ Type Questions for ISC Physics Class-12

---

Question 1:  According to Maxwell’s hypothesis, a changing electric field gives rise to

(a) an e.m.f

(b) electric displacement current

(c) magnetic field

(d) pressure gradient

Answer: (c) magnetic field

Question 2:  The current in the electric circuit which arises due to flow of electrons in the connecting wires of the circuit in a defined closed path is called

(a) alternating current

(b) direct current

(c) conduction current

(d) displacement current

Answer: (c) conduction current 

Question 3: An electromagnetic wave can be produced, when charge is

(a) moving with a constant velocity

(b) moving in a circular orbit

(c) falling in an electric field

(d) both (b) and (c)

Answer: (d) both (b) and (c)

Question 4:   An electromagnetic wave propagating along north has its electric field vector upwards. Its magnetic field vector point towards

(a) north

(b) east

(c) west

(d) downwards

Answer: (b) east

Question 5: Which of the following statement is false for the properties of electromagnetic waves?

(a) Both electric and magnetic field vectors attain the maxima and minima at the same place and same time.

(b) The energy in electromagnetic waves is divided equally between electric and magnetic field vectors.

(c) Both electric and magnetic field vectors are parallel to each other and perpendicular to the direction of propagation of wave.

(d) These waves do not require any material medium for propagation.

Answer: (c) Both electric and magnetic field vectors are parallel to each other and perpendicular to the direction of propagation of wave.

Question 6: A charged particle oscillates about its mean equilibrium position with a frequency of 109 Hz. The frequency of electromagnetic waves produced by the oscillator is

(a) 10⁶ Hz

(b) 10⁷ Hz

(c) 10⁸ Hz

(d) 10⁹ Hz

Answer: (d) 10⁹ Hz

Question 7: The ultra high frequency band of radio waves in electromagnetic wave is used as in

(a) television waves

(b) cellular phone communication

(c) commercial FM radio

(d) both (a) and (c)

Answer: (b) cellular phone communication

Question 8: The waves used by artificial satellites for communication is

(a) microwaves

(b) infrared waves

(c) radio waves

(d) X-rays

Answer: (a) microwaves

Question 9:  Which of the following electromagnetic waves is used in medicine to destroy cancer cells?

(a) IR-rays

(b) Visible rays

(c) Gamma rays

(d) Ultraviolet rays

Answer: (c) Gamma rays

Question 10: The electromagnetic waves do not transport

(a) energy

(b) charge

(c) momentum

(d) information

Answer: (b) charge

Question 11:  Which of the following has/have zero average value in a plane electromagnetic wave?

(a) Both magnetic and electric fields

(b) Electric field only

(c) Magnetic field only

(d) None of these

Answer: (a) Both magnetic and electric fields

Question 12: The conduction current is same as displacement current when source is

(a) ac only

(b) dc only

(c) either ac or dc

(d) neither dc nor ac

Answer: (c) either ac or dc

Question 13:  In an electromagnetic wave, the electric and magnetic fields are 100 V m^–1 and 0.265 A m^–1. The maximum energy flow is

(a) 26.5 W/m²

(b) 36.5 W/m²

(c) 46.7 W/m²

(d) 765 W/m²

Answer: (a) 26.5 W/m² 

Question 14:  Radio waves do not penetrate in the band of

(a) ionosphere

(b) mesosphere

(c) troposphere

(d) stratosphere

Answer: (a) ionosphere 

Question 15: If the wavelength of electromagnetic radiation is doubled, what will happen to the energy of photons?

(a) Doubled

(b) Halved

(c) Remains the same

(d) Becomes zero

Answer: (b) Halved

Question 16: Maxwell in his famous equations of electromagnetism introduced the concept of

(a) ac current

(b) displacement current

(c) impedance

(d) reactance

Answer: (b) displacement current

Question 17:   If a variable frequency ac source connected to a capacitor then with decrease in frequency, the displacement current will

(a) increase

(b) decrease

(c) remain constant

(d) first decrease then increase

Answer: (b) decrease

Question 18: Is the ratio of frequencies of UV rays and IR rays in the glass more than, less than or equal to 1?

(a) Insufficient data

(b) Equal to 1

(c) Less than 1

(d) More than 1

Answer: (d) More than 1

Question 19:  An electron oscillating with a frequency of 3 × 10⁶ Hz, would generate

(a) X-rays

(b) ultraviolet rays

(c) radio waves

(d) microwaves

Answer: (c) radio waves 

Question 20:  Select the wrong statement. EM waves

(a) are transverse in nature.

(b) travel in free space at a speed of light.

(c) are produced by accelerating charges.

(d) travel in all media with same speed.

Answer: (d) travel in all media with same speed.

Question 21:  The polarisation of electromagnetic wave is in

(a) the directions of electric and magnetic field

(b) the directions of electric field

(c) the direction of magnetic field

(d) can not be polarized

Answer: (b) the directions of electric field

Question 22: Which of the following has/have zero average value in a plane electromagnetic wave?

(a) Both magnetic and electric field

(b) Electric field only

(c) Magnetic energy

(d) Electric energy

Answer: (a) Both magnetic and electric field

Question 23: If a variable frequency ac source is connected to a capacitor then with decrease in frequency the displacement current will

(a) increase

(b) decrease

(c) remains constant

(d) first decrease then increase

Answer: (b) decrease

Question 24: If a variable frequency ac source connected to a capacitor then with decrease in frequency, the displacement current will

(a) increase

(b) decrease

(c) remain constant

(d) first decrease then increase

Answer: (b) decrease

Question 25:  The range of wavelength of visible light is

(a) 50 Å to 500 Å

(b) 4000 Å to 8000 Å

(c) 9000 Å to 25,000 Å

(d) 15,000 Å to 25,000 Å

Answer: (b) 4000 Å to 8000 Å

Question 26: What is the ratio of the speed of infrared and ultraviolet rays in a vacuum?

(a) 1:5

(b) 2:1

(c) 1

(d) 0

Answer: (c) 1

Question 27:  Displacement current goes through the gap between the plates of a capacitor when the charge on the capacitor

(a) is changing with time

(b) decreases

(c) does not change

(d) decreases to zero

Answer: (a) is changing with time 

Question 28: Which basic oscillatory circuit is used these days to produce electromagnetic waves?

(a) LC oscillatory circuit

(b) LCR circuit

(c) Inductive circuit

(d) Capacitive circuit

Answer: (a) LC oscillatory circuit

Question 29:  The electromagnetic radiation used in food processing sterilizing agent is

(a) microwaves

(b) UV rays

(c) gamma rays

(d) radio waves

Answer: (b) UV rays

Question 30: For which frequency of light, the human eye is most sensitive?

(a) 55.405 × 10¹⁴ Hz

(b) 95.405 × 10¹⁴ Hz

(c) 5.405 × 10¹⁴ Hz

(d) 79.405 × 10¹⁴ Hz

Answer: (c) 5.405 × 10¹⁴ Hz

Question 31: The speed of electromagnetic wave is same for