Question

All types of electromagnetic radiation possess same:
A. wavelength
B. frequency
C. energy
D. velocity when passed through vacuum

Answer 1

Hint: In order to know that which characteristic of electromagnetic radiation remain same among given four options, we will first discuss about electromagnetic radiation and then will get to know about each option one by one and later conclude which characteristic remain same for electromagnetic radiations.

Complete answer:
All the radiations which have both electric and magnetic fields and travel through space such as radio waves, infra-red waves are known as electromagnetic waves carrying energy.

Now option (A) wavelength of an electromagnetic wave is defined as the distance between two successive crest or trough regions of the electromagnetic radiation and when an electromagnetic wave and its different for different types of electromagnetic waves.

option (B) Frequency is defined as the number of waves that passes through space in one second and for different electromagnetic waves, its different value so it also doesn't remain the same.

option (C) Energy is carried by electromagnetic radiation which is calculated as $E = h\nu $ where h is Planck’s constant and $\nu $ denote the frequency of wave so, frequency is different for each waves, hence Energy is also different for each type of electromagnetic radiations.

option (D) Since, In free space all types of electromagnetic waves moves with same speed with the speed of light which has a constant value in vacuum $c = 3 \times {10^8}m{s^{ - 1}}$ so, all electromagnetic radiations possess same velocity when passed through vacuum.

Hence, the correct option is D.

Note: It should be remembered that, the velocity of electromagnetic radiation may change while it goes from one medium to another for example the velocity of radiations in glass medium will be different from free space but maximum velocity of all radiations is the velocity of light which is universal speed limit.