Free NEET Physics multiple-choice questions on EM Spectrum & Properties. Attempt each question and reveal the answer with a full explanation.
Which of the following is NOT an electromagnetic wave? β-rays X-rays Radio waves Light waves Which region of the electromagnetic spectrum is used for examining the internal structure of crystals using diffraction patterns? X-rays Gamma rays Ultraviolet Infrared Which region of the electromagnetic spectrum is utilized in 'Remote Sensing' satellites for monitoring vegetation and crop health? Infrared X-rays Ultraviolet γ -rays The wave number ( k ) of an electromagnetic wave is 2 10 7 rad/m . What is the wavelength of this wave? 3.14 10 -7 m 6.28 10 -7 m 1.57 10 -7 m 2 10 -7 m The frequency of an electromagnetic wave used in satellite communication is usually in the range of: 1 GHz - 30 GHz 30 MHz - 300 MHz 540 kHz - 1600 kHz 10 14 Hz - 10 15 Hz The frequency of oscillation of the electric field in a plane electromagnetic wave is 5 10 14 Hz . This wave is in which region of the spectrum? Visible (Green) Infrared Microwave X-ray A radio can tune to any station in the 7.5 MHz to 12 MHz band. What is the corresponding wavelength band? 25 m to 40 m 2.5 m to 4.0 m 250 m to 400 m 7.5 m to 12 m What is the frequency of an electromagnetic wave that has a wavelength of 3 nm in vacuum? 10 17 Hz 10 14 Hz 10 11 Hz 10 19 Hz Which transition in an atom typically produces radiations in the visible and ultraviolet regions of the spectrum? Outer shell electronic transitions Inner shell electronic transitions Nuclear transitions Molecular vibrations The frequency of a certain EM radiation is 2 10 14 Hz . To which part of the spectrum does it belong? Infrared Visible Ultraviolet Microwaves Which part of the electromagnetic spectrum has wavelengths ranging from 400 nm to 1 nm ? Ultraviolet Infrared Visible X-rays The wavelength of a 100 eV photon belongs to which part of the spectrum? Ultraviolet X-ray Visible Infrared The wavelength of light visible to the human eye is in the range: 400 nm to 700 nm 1 nm to 100 nm 1 mm to 10 cm 10 -12 m to 10 -10 m Which type of electromagnetic radiation is primarily responsible for the 'Photokeratitis' (snow blindness) in humans exposed to high altitudes or welding arcs? Ultraviolet-B radiation Infrared radiation Microwaves Visible light A radio wave has a frequency of 12 MHz . What is its wave number k in vacuum? 0.251 rad/m 0.040 rad/m 3.14 rad/m 1.25 rad/m Which part of the electromagnetic spectrum is sometimes called 'cold light' or involves the 'atmospheric window' used by ground-based radio telescopes? Radio waves Gamma rays Ultraviolet Visible light The energy of a photon of frequency 3 10 18 Hz is approximately: 12.4 keV 1.24 eV 124 eV 1.24 MeV The range of wavelengths for the visible spectrum is approximately 400 nm to 700 nm . What is the approximate frequency range? 4.3 10 14 Hz to 7.5 10 14 Hz 4.3 10 12 Hz to 7.5 10 12 Hz 4.3 10 16 Hz to 7.5 10 16 Hz 10 14 Hz to 10 15 Hz The frequency of an electromagnetic wave is 2 10 14 Hz . Its wave number in vacuum is: 4.18 10 6 rad/m 2.14 10 6 rad/m 6.28 10 6 rad/m 1.33 10 6 rad/m Visible light belongs to the range of wavelengths from approximately 400 nm to 700 nm . Light of wavelength 500 nm will have a color closest to: Green Red Violet Yellow The wavelength of an electromagnetic wave with a photon energy of 1.24 eV lies in which region of the spectrum? Infrared Visible Ultraviolet Microwaves Which of the following regions of the electromagnetic spectrum is used in 'Satellite TV' and 'Direct Broadcast Satellite' (DBS) systems? Microwaves Radio waves Infrared Visible light Which part of the electromagnetic spectrum is used to check the growth of crops and for identifying different types of soils from space? Infrared X-rays Microwaves Gamma rays Which part of the electromagnetic spectrum is used for television broadcasting using high-frequency (VHF and UHF) bands? Radio waves Microwaves Infrared Visible light The 'Lyman-alpha' emission of Hydrogen has a frequency of 2.47 10 15 Hz . In which region of the EM spectrum does this fall? Ultraviolet Visible Infrared X-rays In the spectrum of electromagnetic waves, the ratio of the wavelengths of visible light to X-rays is approximately: 10 3 1 10 -3 10 6 If the human eye is most sensitive to green light of wavelength 555 nm , what is the energy of one such photon in electron-volts (eV)? 2.23 eV 1.12 eV 3.45 eV 4.50 eV What is the amplitude of the magnetic field for an EM wave in vacuum if the average intensity is 0.1 W/m 2 ? 2.9 10 -8 T 1.2 10 -7 T 4.1 10 -9 T 8.5 10 -8 T What is the peak magnetic field B 0 produced by a 100 W light bulb (assumed to be a point source emitting isotropically) at a distance of 3 m from the bulb? 9.4 10 -8 T 1.3 10 -7 T 2.1 10 -6 T 4.5 10 -9 T Which type of electromagnetic wave is used to study the molecular structure and properties of materials through ESR (Electron Spin Resonance)? Microwaves Radio waves Infrared Ultraviolet A point source of electromagnetic radiation has an average power output of 1500 W . The maximum value of the electric field at a distance of 3 m from the source is approximately: 100 V/m 200 V/m 50 V/m 150 V/m An electromagnetic wave travelling in a lossless dielectric medium having a dielectric constant, r=9 , has the electric field, E x=E 0 (kz-2 10 6 t) Vm -1 where E 0 is the amplitude and k is the wave vector. Among the following options, the incorrect choice is: The speed of the electromagnetic wave inside the medium is 10 8 ms -1 The wavelength of the electromagnetic wave inside the medium is 300 m The magnetic field is given by the relation B y= B 0 v (kz-2 10 6 t) where v is the speed of the electromagnetic wave inside the medium The direction of propagation of the electromagnetic wave is along +z The following table presents the part of the electromagnetic spectrum and their corresponding major applications. The correct option is: P-I, Q-II, R-III, S-IV P-I, Q-IV, R-II, S-III P-II, Q-I, R-IV, S-III P-II, Q-IV, R-III, S-I The 'Lyman-alpha' emission line, which is critical in astronomy for observing distant galaxies, occurs at a wavelength of approximately 121.6 nm . This radiation belongs to which part of the spectrum? Ultraviolet Visible Infrared X-rays In a microwave oven, the frequency of the microwaves is chosen such that it resonates with the rotational levels of water molecules. This frequency is roughly: 2.45 GHz 2.45 MHz 50 Hz 10 14 Hz A point source of electromagnetic radiation has an average power of P . The average intensity I at a distance r from the source is: P 4 r 2 P r 2 P r 2 P 2 r 2 The wavelength of the radiation emitted by a radio transmitter operating at a frequency of 1500 kHz is: 200 m 20 m 2000 m 2 m Which region of the electromagnetic spectrum has frequencies lower than visible light but higher than microwaves? Infrared Ultraviolet X-rays Radio waves The energy of an electromagnetic wave is E . If its frequency is doubled, then the energy of its photon becomes: 2E E/2 4E E Which radiation is used to detect fake currency notes? Ultraviolet rays Infrared rays Radio waves Gamma rays Which region of the electromagnetic spectrum is used in 'thermal' imaging for weather forecasting and military applications? Infrared Ultraviolet Microwaves Radio waves If the frequency of an electromagnetic wave is 30 MHz , its wavelength in vacuum is: 10 m 1 m 100 m 0.1 m The frequency of rotation of water molecules in a microwave oven is chosen to be around 2.45 GHz . What is the wavelength of these microwaves? 12.2 cm 1.22 cm 12.2 m 0.122 mm Which property of electromagnetic waves confirms that they do not require any material medium for propagation? They can be polarized They travel in vacuum with speed c They are transverse in nature They carry energy and momentum Which of the following is the correct order of increasing energy of photons? Radio waves < Microwaves < Infrared < Visible Visible < Infrared < Microwaves < Radio waves Microwaves < Radio waves < Visible < Infrared Infrared < Visible < Radio waves < Microwaves The wavelength of the radiation emitted by a 100 MHz FM radio station is: 3 m 30 m 0.3 m 300 m X-rays, gamma rays and microwaves travelling in vacuum have: Same speed but different wavelengths Same wavelength but different speeds Same frequency but different speeds Different speeds and different wavelengths Which of the following is used in thermal imaging cameras? Infrared waves X-rays Ultraviolet rays Microwaves Wave of wavelength 10 cm is likely to be: Microwaves X-rays Gamma rays Visible light In a microwave oven, the frequency of the microwaves is selected to match the resonant frequency of water molecules. This phenomenon is an example of: Dielectric heating Photoelectric effect Compton effect Thermionic emission Which of the following electromagnetic waves is used in 'night vision' goggles? Infrared waves Ultraviolet waves Microwaves X-rays A point source of radiation of 100 W emits light isotropically. The intensity of radiation at a distance of 2 m from the source is: 1.99 W/m 2 7.96 W/m 2 25 W/m 2 50 W/m 2 Arrange the following in increasing order of their frequency: (i) Gamma rays, (ii) Blue light, (iii) Infrared, (iv) Microwaves. iv < iii < ii < i i < ii < iii < iv iv < ii < iii < i iii < iv < ii < i Gamma rays are highly penetrating because they possess: High frequency and no charge Low frequency and positive charge High frequency and negative charge Low frequency and no charge The wavelength of an electromagnetic wave in vacuum is 300 m . What is its frequency? 1 MHz 100 MHz 1 GHz 10 MHz The waves used for communication through cellular phones are: Radio waves Infrared waves Ultraviolet waves Gamma rays Which of the following has the shortest wavelength? Gamma rays X-rays Ultraviolet rays Microwaves Infrared radiation is often called heat waves because: Water molecules in most materials readily absorb infrared waves and increase thermal motion. They are produced by cold bodies. They have very high frequencies like X-rays. They travel slower than visible light. The wavelength of X-rays is of the order of: 1 Å 1 mm 1 cm 1 μm Which part of the electromagnetic spectrum is used to treat muscular strain in physiotherapy? Infrared Ultraviolet X-rays Microwaves Which of the following electromagnetic radiations has the highest frequency? Gamma rays X-rays Ultraviolet rays Microwaves The frequency of a wave is 6 10 14 Hz . When it travels from vacuum into a medium of refractive index 1.5 , its frequency will be: 6 10 14 Hz 4 10 14 Hz 9 10 14 Hz 3 10 14 Hz Which property of electromagnetic waves is responsible for the 'blue' color of the sky? Scattering Interference Diffraction Refraction The electromagnetic waves used in water purifiers to kill germs are: UV rays Infrared rays X-rays Gamma rays Which of the following properties is NOT shared by all parts of the electromagnetic spectrum in vacuum? Wavelength Speed Transverse nature Propagation without medium The speed of electromagnetic waves in a medium depends on: Both permittivity and permeability of the medium Only the permittivity of the medium Only the permeability of the medium The intensity of the wave The frequency of an electromagnetic wave is 2 10 6 Hz . What is its wavelength in vacuum? 150 m 600 m 300 m 75 m Who was the first scientist to experimentally discover X-rays while working with cathode ray tubes? Wilhelm Roentgen Johann Ritter William Herschel Heinrich Hertz In the context of the electromagnetic spectrum, which radiation is emitted during the transition of an atomic nucleus from an excited state to a ground state? γ -rays X-rays UV rays Cosmic rays Which type of electromagnetic radiation is used in 'Computed Tomography' (CT) scans to produce detailed images of the internal organs? X-rays γ -rays Microwaves Radio waves Short-wave radio broadcasts use the ionosphere for long-distance communication. This is possible because the ionosphere: Reflects radio waves of certain frequencies Absorbs radio waves of all frequencies Refracts radio waves into outer space Polarizes the incoming radio waves Which part of the electromagnetic spectrum is used in 'Bragg's Law' for the study of the internal structure of crystals? X-rays γ -rays UV rays Visible light The frequency band used for FM (Frequency Modulation) radio broadcasting is approximately: 88 MHz to 108 MHz 540 kHz to 1600 kHz 300 MHz to 3 GHz 10 GHz to 30 GHz The frequency of oscillation of water molecules in a microwave oven is approximately: 2.45 GHz 2.45 MHz 2.45 THz 2.45 Hz If the wavelength of an electromagnetic wave in vacuum is 1 Å , it is likely to be: X-ray Ultraviolet γ -ray Infrared Which gas in the Earth's atmosphere is the primary absorber of Infrared radiation, contributing to the greenhouse effect? Carbon dioxide Nitrogen Oxygen Argon In a vacuum, the speed of all electromagnetic waves ( c ): Is a universal constant independent of frequency Increases with the frequency of the wave Decreases as the wavelength increases Depends on the intensity of the radiation Which part of the electromagnetic spectrum is used in RADAR systems? Microwaves Infrared waves Ultraviolet rays Gamma rays Which type of waves are used in point-to-point communication systems such as satellite links? Microwaves Sky waves Ground waves Acoustic waves When an electromagnetic wave enters a denser medium from vacuum, which property remains unchanged? Frequency Wavelength Speed Amplitude Fluorescent tubes often use a coating on the inside to convert which type of radiation into visible light? Ultraviolet Infrared X-rays Microwaves Which of the following electromagnetic radiations is used for 'sterilizing' surgical instruments and killing bacteria? Ultraviolet Infrared Radio waves Visible light Which type of electromagnetic radiation has the property of passing through thick wood or thin metal sheets but is stopped by lead? X-rays Ultraviolet Infrared Visible light A radio station transmits at a frequency of 1000 kHz . The wavelength of the transmission is: 300 m 30 m 3000 m 3 m Which type of electromagnetic radiation is produced by transitions of inner shell electrons in atoms? X-rays -rays UV rays Infrared An Indian scientist who produced electromagnetic waves of very short wavelength ( 5 mm to 25 mm ) in a laboratory was: Jagadish Chandra Bose C.V. Raman Homi J. Bhabha Satyendra Nath Bose Which region of the electromagnetic spectrum has a frequency range of approximately 10 14 Hz to 10 15 Hz ? Visible light Infrared Ultraviolet Microwaves Greenhouse effect is mainly due to the absorption of: Infrared rays by the atmosphere Ultraviolet rays by the ozone layer Radio waves by the ionosphere Visible light by the soil The frequencies of X -rays, Y -rays and Ultraviolet rays are a, b and c respectively. Then: b > a > c a > b > c c > b > a b > c > a If the wavelength of an electromagnetic radiation is doubled, what happens to the energy of its photon? It becomes half It becomes double It becomes four times It remains the same Which of the following is the correct order of increasing penetration power? Radio waves < Microwaves < Visible Light < X-rays X-rays < Visible Light < Microwaves < Radio waves Visible Light < Radio waves < X-rays < Microwaves Microwaves < Radio waves < Visible Light < X-rays Which type of electromagnetic radiation is produced by the bombardment of high-speed electrons on a metal target of high atomic number? X-rays Gamma rays Ultraviolet rays Infrared rays According to the electromagnetic spectrum, which of the following represents the correct sequence of increasing wavelength? Gamma rays, X-rays, UV, Visible, IR, Microwaves, Radio waves Radio waves, Microwaves, IR, Visible, UV, X-rays, Gamma rays UV, Visible, IR, Microwaves, Gamma rays, X-rays, Radio waves X-rays, Gamma rays, UV, Visible, IR, Microwaves, Radio waves A radio wave of frequency 3 MHz passes from vacuum into a medium of dielectric constant 4 . What is the frequency of the wave in the medium? 3 MHz 1.5 MHz 6 MHz 12 MHz Which of the following is responsible for the 'heating effect' of solar radiation? Infrared rays Ultraviolet rays X-rays Gamma rays The correct order of increasing photon energy for the following electromagnetic radiations is: (i) Blue light, (ii) Microwaves, (iii) X-rays, (iv) Radio waves. (iv) < (ii) < (i) < (iii) (ii) < (iv) < (i) < (iii) (iv) < (ii) < (iii) < (i) (iii) < (i) < (ii) < (iv) Which of the following electromagnetic waves has the highest ionizing power? Gamma rays X-rays Ultraviolet rays Microwaves Who discovered Infrared radiation by observing the heating effect beyond the red end of the visible spectrum? William Herschel Johann Ritter James Clerk Maxwell Heinrich Hertz Which type of electromagnetic radiation is used in the study of crystal structure through diffraction experiments? X-rays Gamma rays Ultraviolet rays Infrared rays Which region of the electromagnetic spectrum is responsible for the 'greenhouse effect' by being trapped by atmospheric gases like CO 2 and CH 4 ? Infrared Ultraviolet Visible Microwaves Which of the following is an effect of Ultraviolet radiation on the human body? Production of Vitamin D Deep tissue heating Sensation of color None of these Which property of electromagnetic waves remains unchanged when they travel from one medium to another? Frequency Wavelength Speed Amplitude What is the order of magnitude of the wavelength for FM radio waves? 1 m 100 m 1 mm 1 km Which type of EM radiation has the property of being reflected by the ionosphere? Radio waves (Short-wave) Visible light X-rays Gamma rays If the wavelength of an electromagnetic radiation is 600 nm , what is the energy of its photon in electron-volts? (Take h = 6.6 10 -34 J s and c = 3 10 8 m/s ) 2.07 eV 1.24 eV 3.10 eV 4.14 eV Which of the following radiations has the highest photon energy? -rays X-rays UV rays Visible light If the wavelength of an electromagnetic wave is = 5 10 -11 m , it belongs to which region of the spectrum? X-rays Gamma rays Ultraviolet Microwaves The electromagnetic wave used in 'point-to-point' communication like Microwave Relay is in the frequency range of: 1 GHz to 300 GHz 100 kHz to 1000 kHz 10 14 Hz to 10 15 Hz 10 18 Hz to 10 22 Hz What is the frequency of an electromagnetic wave whose wavelength is 10 m ? 30 MHz 3 MHz 300 MHz 30 kHz Ozone layer blocks radiation of wavelength: less than 3 10 -7 m more than 3 10 -7 m between 4 10 -7 m and 8 10 -7 m between 10 -2 m and 10 m If the frequency of an EM wave is 60 GHz , then it belongs to which part of the spectrum? Microwaves Radio waves Infrared Visible If the frequency of a wave is 10 15 Hz , it belongs to: Ultraviolet Microwave Infrared Radio wave Which part of the EM spectrum is used in 'LASIK' eye surgery? Ultraviolet Infrared Microwaves X-rays If the wavelength of an electromagnetic wave is = 21 cm , it belongs to which region of the spectrum? Short radio waves (Microwaves) Infrared Ultraviolet Visible The wavelength of the 21-cm line emitted by hydrogen atoms in interstellar space belongs to the: Radio waves Infrared Visible X-rays Which of the following instruments is commonly used to detect Infrared radiation? Thermopile Photographic plate Geiger counter Ionization chamber Which specific sub-category of Ultraviolet radiation is primarily responsible for causing sunburn and skin cancer? UV-B UV-A UV-C Vacuum UV Welders wear special goggles or face masks with glass windows to protect their eyes from: Ultraviolet rays Infrared rays Microwaves Radio waves The wavelength of the 'Sodium D lines' in the visible spectrum is approximately 589 nm . What is the corresponding frequency? 5.09 10 14 Hz 5.09 10 12 Hz 1.76 10 14 Hz 3.24 10 15 Hz Arrange the following regions of the electromagnetic spectrum in decreasing order of their wavelength: (P) Infrared, (Q) Ultraviolet, (R) Microwaves, (S) X-rays. R > P > Q > S P > R > Q > S R > Q > P > S S > Q > P > R What is the energy of a photon corresponding to a radio wave of frequency 1 MHz ? ( h = 6.63 10 -34 J s ) 6.63 10 -28 J 6.63 10 -34 J 1.98 10 -25 J 4.14 10 -15 J Which scientist discovered Ultraviolet radiation by observing the darkening of silver chloride? Johann Ritter William Herschel James Clerk Maxwell Isaac Newton What is the approximate frequency of an electromagnetic wave whose wavelength is equal to the diameter of a typical atom ( 10 -10 m )? 3 10 18 Hz 3 10 16 Hz 3 10 15 Hz 3 10 20 Hz Which of the following describes the correct order of photon energy for different regions of the EM spectrum? E γ > E X-ray > E Visible > E Radio E Radio > E Visible > E X-ray > E γ E Visible > E X-ray > E γ > E Radio E γ > E Radio > E Visible > E X-ray In airport security, which type of electromagnetic radiation is used in 'millimeter-wave' scanners to detect hidden objects? Microwaves Soft X-rays Infrared Ultraviolet The frequency of an electromagnetic wave is 6.0 10 14 Hz . This wave belongs to which region of the spectrum? Visible Infrared Ultraviolet Microwave Calculate the wavelength of an electromagnetic wave with a frequency of 1 THz ( 10 12 Hz ) in vacuum. 0.3 mm 3 cm 3 μm 300 nm Wien's Displacement Law relates the peak wavelength ( λ m ) of blackbody radiation to the absolute temperature ( T ) as λ m T = b . This implies that as temperature increases, the peak radiation shifts towards: Higher frequencies Lower frequencies Longer wavelengths Radio wave region