Electromagnetic Waves Online MCQ Practice Test: Set-1

1) An energy is a measure of the ability to do work. It comes in many forms. It can transform from one type to another type. Batteries are an example of potential (or stored) energy. Object-in-motion is an example of kinetic energy. Electrons and protons are charged particles. When they move, they create electromagnetic fields. Scientist “James Clerk Maxwell” explained the scientific theory of electromagnetic wave. He paired electrical fields and magnetic fields together to form electromagnetic waves. WHAT IS/ARE TRANSPORT BY ELECTROMAGNETIC WAVES?

2) In the electromagnetic spectrum, gamma-rays have (1) smallest wavelengths; and (2) the most energy. Gamma rays are generated: (1) by radioactive atoms; or (2) by nuclear explosions. Gamma-rays can kill living cells, due to it in medical science; it is used to kill cancerous cells. WHICH IS INCORRECT? GAMMA RAYS HAVE THE VELOCITY OF:

3) Photons are described as energy packets. Photon contains energy that cannot be divided. This energy is stored as an oscillating electric field. These fields may oscillate at almost any frequency. The packets of energy of photon can be transmitted over vast distances with no decay in energy or speed. Photons travel at the speed of light, 2.997 x 108 m/s in empty space. The speed of a photon through space can be directly derived from the speed of an electric field through free space. Photons have similar properties to electromagnetic waves. Each photon has a wavelength and a frequency. The wavelength of a photon is defined as the distance between two peaks of the electric field with the same vector. The frequency of a photon is defined as how many wavelengths a photon propagates each second. Unlike an electromagnetic wave, a photon cannot actually be of a color. Instead, a photon will correspond to light of a given color. A single photon cannot have color because it cannot be detected by the human eye. THE ENERGY FOR 1A⁰ PHOTON IS OF ORDER OF:

4) In a vacuum, the speed at which electromagnetic waves move is:

5) Infrared radiation (IR), or infrared light, is a type of radiant energy that is invisible to human eyes but that we can feel as heat. All objects in the universe emit some level of IR radiation, but two of the most obvious sources are the SUN and FIRE. IR is a type of electromagnetic radiation, a continuum of frequencies produced when atoms absorb and then release energy. From HIGHEST to LOWEST FREQUENCY, electromagnetic radiation includes: (i) GAMMA-RAYS; (ii) X-RAYS; (iii) ULTRAVIOLET RADIATION; (iv) VISIBLE LIGHT OF RED COLOUR; (v) INFRARED RADIATION; (vi) MICROWAVES; and (vii) RADIO WAVES. Together, these types of radiation make up the electromagnetic spectrum. According to NASA, British astronomer WILLIAM HERSCHEL discovered infrared light in 1800. Within the electromagnetic spectrum, infrared waves occur at frequencies above those of microwaves and just below those of red visible light, hence the name "infrared." Waves of infrared radiation are longer than those of visible light. IR frequencies range from about 300 gigahertz (GHz) up to about 400 terahertz (THz), and wavelengths are estimated to range between 1,000 micrometers (µm) and 760 nanometres (2.9921 inches). The "near-infrared" waves, which are closer to visible light of red colour on the electromagnetic spectrum, do not emit any detectable heat and are what is discharged from a TV remote control to change the channels. The "far-infrared" waves, which are closer to the microwave on the electromagnetic spectrum, can be felt as intense heat, such as the heat from sunlight or fire. IR radiation is one of the three ways heat is transferred from one place to another. Everything with a temperature above around 5 degrees Kelvin (minus 450 degrees Fahrenheit or minus 268 degrees Celsius) emits IR radiation. The sun gives off half of its total energy as IR, and much of the star's visible light is absorbed and re-emitted as IR. THE INFRA-RED SPECTRUM LIES BETWEEN:

6) Equation of Planck E = hv. E denotes energy (in Joules), v denotes frequency [in reciprocal seconds, written s^-1 or Hertz (Hz)-1Hz = 1 s^-1], and h denotes Planck's constant. The connection between energy and frequency in a black body is supposedly defined by this equation. A black body is an object that is a perfect emitter and absorber, able to emit any radiation that might possibly exist. Black bodies are not exclusively black. An illustration of a black body is the Sun. The fundamental implication of Planck's equation was that light arrived in discrete (finite) packets that were multiples of hv.

ENERGY-FREQUENCY RELATIONSHIP E = hv CANNOT BE APPLIED TO:

7) The momentum of a photon is directly proportional to its frequency and inversely proportional to its wavelength. If the wavelength of a photon is known, its momentum can be calculated. Similarly, if the frequency of a photon is known, its momentum can be calculated. WHAT IS THE FORMULA FOR CALCULATION OF MOMENTUM OF A PHOTON?

8) We knew that a photon is an elementary force-carrying particle. It has a zero mass (rest mass). It travels at the speed of light in vacuum. It is stable with no electric charge. It exhibits both wave-like and particle-like properties, called wave-particle duality. The magnitude of photon energy is directly proportional to frequency (E = hν) and inversely proportional to wavelength (E = hc/λ). Photons are called x-rays if they are produced by electron interactions. An x-ray photon has a wavelength of 0.01 to 10 nanometres, with a frequency of 3×10¹⁶ Hz to 3×10¹⁹ Hz. It possesses energy (100 eV to 100 keV) to break molecular bonds and ionize atoms making it, by definition, ionizing radiation. AN X’-RAYS PHOTON HAS:

9) 10 eV PHOTONS ARE TERMED AS:

10) Electromagnetic waves have a:

11) German scientist WILHELM CONRAD ROENTGEN made the first X-ray observation in 1895. He found that shooting x-ray beams through hands and arms produced precise photographs of the bones inside.

THE X’-RAY PHOTONS ARE:

12) We are using electromagnetic waves, when we listen to the radio, or watch smart TV, or cook dinner in a microwave. Means, radio waves, television waves, and micro-waves are all types of electromagnetic waves. They only differ from each other in wave-length. Wave-length is the distance between one highest point (called crest) to the next highest point of the wave. WHICH OF THE FOLLOWING IS NOT AN ELECTROMAGNETIC WAVE?

13) We knew that photons are known for their role as the ‘light’ carrying particle, but that is only a part of their job. Photons are also the ‘energy’ carrier particles for various other kinds of waves, which are taken together to form the ELECTROMAGNETIC RADIATIVE (EMR) spectrum. EMR are characterized in different parts by wavelength and frequency. In order of increasing frequency / decreasing wavelength, they can be: (1) RADIO WAVES; (2) MICROWAVES; (3) INFRARED RADIATION; (4) VISIBLE LIGHT; (5) ULTRAVIOLET RADIATION; (6) X-RAYS; and (7) GAMMA RAYS. WHICH OF THE FOLLOWING TYPE OF ELECTROMAGNETIC WAVES HAS MAXIMUM WAVELENGTH?

14) What is the frequency of X’-rays photon having wavelength 2A⁰ ?

15) THE PHOTON ENERGY FOR 0.5 A⁰ X’-RAYS IS:

16) WHICH OF THE FOLLOWING STATEMENTS IS INCORRECT?

17) Both the E and B fields that are present in electromagnetic waves are aligned:

18) A photon is the smallest amount or quantity of electromagnetic radiation. It is the basic unit of all light. Photons are always in motion. In a vacuum (gap), it travels at a constant speed of 2.998 x 108 m/s. It is called speed of light. Few basic properties of photons are: (1) They have zero mass and rest energy; (2) They only exist as moving particles; (3) They are fundamental particles regardless of lacking rest mass; (4) They have no electric charge; (5) They are stable; (6) They carry energy and momentum which are dependent on the frequency; (7) They can have interactions with other particles such as electrons, such as the Compton effect; (8) They can be destroyed or created by many natural processes, for example, when radiation is absorbed or emitted; and (9) In empty space, they travel at the speed of light. WHAT IS THE ENERGY ASSOCIATED WITH A PHOTON?

19) A field represents “what an object would experience related to a force at a given point in space”. A magnetic field is a field explaining the magnetic impact on an object in space. An electric field is a field defined by the magnitude (result) of the electric force at any given point in space. WHAT IS THE ANGLE BETWEEN ELECTRIC AND MAGNETIC FIELD VECTORS IN ELECTROMAGNETIC WAVE?

20) Electromagnetic waves are transverse waves with a wide range of different properties and uses. Its common properties are called electromagnetic spectrum. All electromagnetic waves: (1) are transverse waves; (2) can travel through a vacuum; (3) travel at exactly the same speed in a vacuum, that is, the speed of light, 300,000,000 m/s; (4) transfer energy from one place to another; (5) can be reflected; and (6) can be refracted. WHICH OF THE FOLLOWING PROPERTIES IS NOT ASSOCIATED WITH ELECTROMAGNETIC WAVES?

21) Electromagnetic waves have magnetic and electric field. Electromagnetic waves are categorized on their frequency. Different types of electromagnetic waves are: (1) RADIO WAVES; (2) MICROWAVES; (3) INFRARED; (4) VISIBLE LIGHT; (5) UV WAVES; (6) X-RAYS; and (7) GAMMA RAYS. WHICH OF THE FOLLOWING TYPE OF ELECTROMAGNETIC WAVES HAS MAXIMUM FREQUENCY?

22) A radio-station transmits waves having frequency 1550 KHz.  What is the corresponding metre-band?

23) Compared to ultraviolet light, x-rays have far higher energies and shorter wavelengths; therefore, scientists normally talk about x-rays in terms of their energy rather than their wavelength. This is mainly due to the fact that x-rays have extremely narrow wavelengths, ranging from 0.03 to 3 nanometers, making some of them barely larger than a single atom of numerous elements.

1A⁰ X’-RAY PHOTONS ARE:

24) Let us denote Ultra-violet by ‘A’, Radio waves by ‘B’, Gamma rays by ‘C’ and X’-rays by ‘D’. ARRANGE A, B, C, AND D IN ASCENDING (INCREASING) ORDER OF THEIR WAVELENGTHS:

25) Similar to Photon (which represents quantum of electromagnetic energy), the gravitational field energy is expressed in: