Question

Which of the following can travel through vacuum?
(A) Light waves
(B) Heat waves
(C) X-ray
(D) Sound waves

Answer 1

Hint: Read the electromagnetic waves.
The electromagnetic waves are produced by accelerated or oscillating charge. These waves do not require any medium for propagation. These waves travel in free space with speed 3×108 ms-1. The orderly distribution of electromagnetic radiation according to their wavelength or frequency is called electromagnetic spectrum. : Radio waves, microwaves, infrared waves, ultraviolet waves, X-waves, gamma-rays.

Complete step by step solution
Light waves: is electromagnetic radiation within the portion of the electromagnetic spectrum that can be perceived by the human eye. Visible light is usually defined as having wavelength in the range of 400-700 nanometer. LIGHT WAVES travel through vacuum.
Heat waves: is the transfer of internal energy in the form of electromagnetic waves. For most bodies on earth the radiation lies in the infrared region of the electromagnetic spectrum. HEAT WAVES travel through vacuum.
X-rays: is also electromagnetic waves which are produced when high energy electrons are stopped suddenly on a metal of high atomic number. X-RAYS travel through vacuum.
Sound waves: sound is Mechanical wave / disturbance from a state of equilibrium that propagates through an elastic material. They don’t travel through vacuum.
Hence, option (A), (B), (C) are correct.

Note
In electromagnetic waves the sinusoidal variation in both electric and magnetic vectors occurs simultaneously. The direction of variation of electric and magnetic field vectors are perpendicular to each other as well as perpendicular to direction of propagation. The electromagnetic waves being uncharged are not deflected by electric and magnetic fields.