Electromagnetic Radiation | MCQs

Explanation

Gamma rays have the shortest wavelength and highest energy in the electromagnetic spectrum.

They are produced in nuclear reactions.

They are used in medical treatments and scientific research.

Explanation

Radio waves were first predicted by James Clerk Maxwell in his theory of electromagnetism (Maxwell's equations) in 1867.

Heinrich Hertz experimentally demonstrated their existence in 1887.

Explanation

X-rays are a type of electromagnetic radiation, like light or radio waves.

Alpha (α) and beta (β) rays are particles, not electromagnetic waves.

Explanation

Electromagnetic waves, including light, travel at the same speed in a vacuum.

It is approximately 299,792 kilometers per second.

Explanation

Radio waves have the longest wavelength in the electromagnetic spectrum, making them the radiation with the maximum wavelength.

Explanation

Explanation

A microwave oven heats food by using electromagnetic radiation at a specific frequency

That resonates with the water molecules in the food, causing them to vibrate and generate heat.

This process of energy transfer due to matching frequencies is called resonance. 

Explanation

The reverse process of X-ray production is related to the "photoelectric effect". 

Photoelectric effect: In this process, a high-energy photon interacts with an atom, transferring all its energy to an electron and ejecting it from the atom.

This is the reverse of X-ray production, where electrons are accelerated to high speeds and generate X-rays when they collide with a target atom. 

Explanation

Energy of one photon (E) = hc / λ

h = 6.626 × 10^-34 Js

c = 3 × 10^8 m/s

λ = 4961 Å = 4961 × 10^-10 m

E = (6.626 × 10^-34 Js × 3 × 10^8 m/s) / (4961 × 10^-10 m)

= 4.007 × 10^-19 J

Number of photons required to do 1 J of work:

n = 1 J / (4.007 × 10^-19 J)

= 2.4961 × 10^18

Explanation