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MCQOPTIONS
This section includes 12583 Mcqs, each offering curated multiple-choice questions to sharpen your Joint Entrance Exam - Main (JEE Main) knowledge and support exam preparation. Choose a topic below to get started.
| 7101. |
If \[{{\lambda }_{v}},\,{{\lambda }_{r}}\] and \[{{\lambda }_{m}}\] represent the wavelength of visible light x-rays and microwaves respectively, then [CBSE PMT 2005] |
| A. | \[{{\lambda }_{m}}>{{\lambda }_{x}}>{{\lambda }_{v}}\] |
| B. | \[{{\lambda }_{v}}>{{\lambda }_{m}}>{{\lambda }_{y}}\] |
| C. | \[{{\lambda }_{m}}>{{\lambda }_{v}}>{{\lambda }_{v}}\] |
| D. | \[{{\lambda }_{v}}>{{\lambda }_{x}}>{{\lambda }_{m}}\] |
| Answer» D. \[{{\lambda }_{v}}>{{\lambda }_{x}}>{{\lambda }_{m}}\] | |
| 7102. |
The intensity of gamma radiation from a given source is I. On passing through 36 mm of lead, it is reduced to \[\frac{I}{8}\]. The thickness of lead which will reduce the intensity to \[\frac{I}{2}\] will be [AIEEE 2005] |
| A. | 18 mm |
| B. | 12 mm |
| C. | 6 mm |
| D. | 9 mm |
| Answer» C. 6 mm | |
| 7103. |
Electromagnetic waves travel in a medium which has relative permeability 1.3 and relative permittivity 2.14. Then the speed of the electromagnetic wave in the medium will be [MH CET 2003] |
| A. | \[13.6\times {{10}^{6}}\,m/s\] |
| B. | \[1.8\times {{10}^{2}}\,m/s\] |
| C. | \[3.6\times {{10}^{8}}\,m/s\] |
| D. | \[1.8\times {{10}^{8}}\,m/s\] |
| Answer» E. | |
| 7104. |
Radiations of intensity \[0.5\,\,W/{{m}^{2}}\] are striking a metal plate. The pressure on the plate is [DCE 2004] |
| A. | \[0.166\times {{10}^{-8}}\,N/{{m}^{2}}\] |
| B. | \[0.332\times {{10}^{-8}}\,N/{{m}^{2}}\] |
| C. | \[0.111\times {{10}^{-8}}\,N/{{m}^{2}}\] |
| D. | \[0.083\times {{10}^{-8}}\,N/{{m}^{2}}\] |
| Answer» B. \[0.332\times {{10}^{-8}}\,N/{{m}^{2}}\] | |
| 7105. |
Which of the following electromagnetic waves have minimum frequency [Pb PET 2000] |
| A. | Microwaves |
| B. | Audible waves |
| C. | Ultrasonic waves |
| D. | Radiowaves |
| Answer» C. Ultrasonic waves | |
| 7106. |
The region of the atmosphere above troposphere is known as [BCECE 2004] |
| A. | Lithosphere |
| B. | Uppersphere |
| C. | Ionosphere |
| D. | Stratosphere |
| Answer» E. | |
| 7107. |
Frequency of a wave is \[6\times {{10}^{15}}Hz.\] The wave is [Orissa PMT 2004] |
| A. | Radiowave |
| B. | Microwave |
| C. | X-ray |
| D. | None of these |
| Answer» E. | |
| 7108. |
An electromagnetic wave of frequency \[\nu =3.0\,MHz\] passes from vacuum into a dielectric medium with permitivity \[\varepsilon =4.0\]. Then [AIEEE 2004] |
| A. | Wavelength is doubled and the frequency remains unchanged |
| B. | Wavelength is doubled and frequency becomes half |
| C. | Wavelength is halved and frequency remains unchanged |
| D. | Wavelength and frequency both remain unchanged |
| Answer» D. Wavelength and frequency both remain unchanged | |
| 7109. |
Which scientist experimentally proved the existence of electromagnetic waves [AFMC 2004] |
| A. | Sir J.C. Bose |
| B. | Maxwell |
| C. | Marconi |
| D. | Hertz |
| Answer» D. Hertz | |
| 7110. |
Which radiation in sunlight, causes heating effect [AFMC 2001] |
| A. | Ultraviolet |
| B. | Infrared |
| C. | Visible light |
| D. | All of these |
| Answer» C. Visible light | |
| 7111. |
Television signals broadcast from the moon can be received on the earth while the TV broadcast from Delhi cannot be received at places about 100 km distant from Delhi. This is because |
| A. | There is no atmosphere around the moon |
| B. | Of strong gravity effect on TV signals |
| C. | TV signals travel straight and cannot follow the curvature of the earth |
| D. | There is atmosphere around the earth |
| Answer» D. There is atmosphere around the earth | |
| 7112. |
A radio receiver antenna that is 2 m long is oriented along the direction of the electromagnetic wave and receives a signal of intensity\[5\times {{10}^{-16}}W/{{m}^{2}}\]. The maximum instantaneous potential difference across the two ends of the antenna is |
| A. | 1.23 mV |
| B. | 1.23 mV |
| C. | 1.23 V |
| D. | 12.3 mV |
| Answer» B. 1.23 mV | |
| 7113. |
An LC resonant circuit contains a 400 pF capacitor and a 100 mH inductor. It is set into oscillation coupled to an antenna. The wavelength of the radiated electromagnetic waves is |
| A. | 377 mm |
| B. | 377 metre |
| C. | 377 cm |
| D. | 3.77 cm |
| Answer» C. 377 cm | |
| 7114. |
An electromagnetic wave going through vacuum is described by \[E={{E}_{0}}\sin (kx-\omega \,t)\]; \[B={{B}_{0}}\sin (kx-\omega \,t)\]. Which of the following equation is true |
| A. | \[{{E}_{0}}k={{B}_{0}}\omega \] |
| B. | \[{{E}_{0}}\omega ={{B}_{0}}k\] |
| C. | \[{{E}_{0}}{{B}_{0}}=\omega k\] |
| D. | None of these |
| Answer» B. \[{{E}_{0}}\omega ={{B}_{0}}k\] | |
| 7115. |
An electromagnetic wave, going through vacuum is described by \[E={{E}_{0}}\sin (kx-\omega \,t)\]. Which of the following is independent of wavelength |
| A. | k |
| B. | w |
| C. | k/w |
| D. | kw |
| Answer» D. kw | |
| 7116. |
A plane electromagnetic wave is incident on a material surface. If the wave delivers momentum p and energy E, then |
| A. | p = 0, E = 0 |
| B. | p ¹ 0, E ¹ 0 |
| C. | p ¹ 0, E = 0 |
| D. | p = 0, E ¹ 0 |
| Answer» C. p ¹ 0, E = 0 | |
| 7117. |
The electromagnetic waves do not transport [Pb. PET 1991] |
| A. | Energy |
| B. | Charge |
| C. | Momentum |
| D. | Information |
| Answer» C. Momentum | |
| 7118. |
The range of wavelength of the visible light is [MP PMT 2000; MP PET 2002] |
| A. | \[10\,\,{AA}\]to\[100\,\,{AA}\] |
| B. | \[4,000\,\,{AA}\]to\[8,000\,\,{AA}\] |
| C. | \[8,000\,\,{AA}\]to\[10,000\,\,{AA}\] |
| D. | \[10,000\,\,{AA}\]to\[15,000\,\,{AA}\] |
| Answer» C. \[8,000\,\,{AA}\]to\[10,000\,\,{AA}\] | |
| 7119. |
A signal emitted by an antenna from a certain point can be received at another point of the surface in the form of [CPMT 1993] |
| A. | Sky wave |
| B. | Ground wave |
| C. | Sea wave |
| D. | Both (a) and (b) |
| Answer» E. | |
| 7120. |
An electromagnetic wave travels along z-axis. Which of the following pairs of space and time varying fields would generate such a wave [CBSE PMT 1994] |
| A. | \[{{E}_{x}},\,{{B}_{y}}\] |
| B. | \[{{E}_{y}},\,{{B}_{x}}\] |
| C. | \[{{E}_{z}},\,{{B}_{x}}\] |
| D. | \[{{E}_{y}},\,{{B}_{z}}\] |
| Answer» B. \[{{E}_{y}},\,{{B}_{x}}\] | |
| 7121. |
In which one of the following regions of the electromagnetic spectrum will the vibrational motion of molecules give rise to absorption [SCRA 1994] |
| A. | Ultraviolet |
| B. | Microwaves |
| C. | Infrared |
| D. | Radio waves |
| Answer» C. Infrared | |
| 7122. |
The oscillating electric and magnetic vectors of an electromagnetic wave are oriented along [CBSE PMT 1994] |
| A. | The same direction but differ in phase by 90° |
| B. | The same direction and are in phase |
| C. | Mutually perpendicular directions and are in phase |
| D. | Mutually perpendicular directions and differ in phase by 90° |
| Answer» D. Mutually perpendicular directions and differ in phase by 90° | |
| 7123. |
Maxwell?s equations describe the fundamental laws of [CPMT 1996] |
| A. | Electricity only |
| B. | Magnetism only |
| C. | Mechanics only |
| D. | Both (a) and (b) |
| Answer» E. | |
| 7124. |
TV waves have a wavelength range of 1-10 meter. Their frequency range in MHz is [KCET 1998] |
| A. | 30-300 |
| B. | 3-30 |
| C. | 300-3000 |
| D. | 3-3000 |
| Answer» B. 3-30 | |
| 7125. |
The 21 cm radio wave emitted by hydrogen in interstellar space is due to the interaction called the hyperfine interaction is atomic hydrogen. the energy of the emitted wave is nearly [CBSE PMT 1998] |
| A. | \[{{10}^{-17}}\]Joule |
| B. | 1 Joule |
| C. | \[7\times {{10}^{-8}}\]Joule |
| D. | \[{{10}^{-24}}\]Joule |
| Answer» E. | |
| 7126. |
In an electromagnetic wave, the electric and magnetising fields are \[100\,V\,{{m}^{-1}}\] and \[0.265\,A\,{{m}^{-1}}\]. The maximum energy flow is [Pb. PMT 1997, 98] |
| A. | \[26.5\,W/{{m}^{2}}\] |
| B. | \[36.5\,W/{{m}^{2}}\] |
| C. | \[46.7\,W/{{m}^{2}}\] |
| D. | \[765\,W/{{m}^{2}}\] |
| Answer» B. \[36.5\,W/{{m}^{2}}\] | |
| 7127. |
According to Maxwell?s hypothesis, a changing electric field gives rise to [AIIMS 1998] |
| A. | An e.m.f. |
| B. | Electric current |
| C. | Magnetic field |
| D. | Pressure radiant |
| Answer» D. Pressure radiant | |
| 7128. |
Light is an electromagnetic wave. Its speed in vacuum is given by the expression [CBSE PMT 1993; MP PMT 1994; RPMT 1999; MP PET 2001; Kerala PET 2001; AIIMS 2002] |
| A. | \[\sqrt{{{\mu }_{o}}{{\varepsilon }_{o}}}\] |
| B. | \[\sqrt{\frac{{{\mu }_{o}}}{{{\varepsilon }_{o}}}}\] |
| C. | \[\sqrt{\frac{{{\varepsilon }_{o}}}{{{\mu }_{o}}}}\] |
| D. | \[\frac{1}{\sqrt{{{\mu }_{o}}{{\varepsilon }_{o}}}}\] |
| Answer» E. | |
| 7129. |
In an apparatus, the electric field was found to oscillate with an amplitude of 18 V/m. The magnitude of the oscillating magnetic field will be [Pb. PMT 1999] |
| A. | \[4\times {{10}^{-6}}\]T |
| B. | \[6\times {{10}^{-8}}\]T |
| C. | \[9\times {{10}^{-9}}\]T |
| D. | \[11\times {{10}^{-11}}\]T |
| Answer» C. \[9\times {{10}^{-9}}\]T | |
| 7130. |
If a source is transmitting electromagnetic wave of frequency \[8.2\times {{10}^{6}}\]Hz, then wavelength of the electromagnetic waves transmitted from the source will be [DPMT 1999] |
| A. | 36.6 m |
| B. | 40.5 m |
| C. | 42.3 m |
| D. | 50.9 m |
| Answer» B. 40.5 m | |
| 7131. |
Heat radiations propagate with the speed of [AMU 2000] |
| A. | a-rays |
| B. | b-rays |
| C. | Light waves |
| D. | Sound waves |
| Answer» D. Sound waves | |
| 7132. |
Energy stored in electromagnetic oscillations is in the form of [Haryana CEET 2000; AFMC 1994] |
| A. | Electrical energy |
| B. | Magnetic energy |
| C. | Both (a) and (b) |
| D. | None of these |
| Answer» D. None of these | |
| 7133. |
Radio waves and visible light in vacuum have [KCET 2000] |
| A. | Same velocity but different wavelength |
| B. | Continuous emission spectrum |
| C. | Band absorption spectrum |
| D. | Line emission spectrum |
| Answer» B. Continuous emission spectrum | |
| 7134. |
Radio wave diffract around building although light waves do not. The reason is that radio waves [AMU 2000] |
| A. | Travel with speed larger than c |
| B. | Have much larger wavelength than light |
| C. | Carry news |
| D. | Are not electromagnetic waves |
| Answer» C. Carry news | |
| 7135. |
Which rays are not the portion of electromagnetic spectrum [Haryana CEET 2000] |
| A. | X-rays |
| B. | Microwaves |
| C. | a-rays |
| D. | Radio waves |
| Answer» D. Radio waves | |
| 7136. |
What is ozone hole [AFMC 2001] |
| A. | Hole in the ozone layer |
| B. | Formation of ozone layer |
| C. | Thinning of ozone layer in troposphere |
| D. | Reduction in ozone thickness in stratosphere |
| Answer» E. | |
| 7137. |
Biological importance of Ozone layer is [CBSE PMT 2001] |
| A. | It stops ultraviolet rays |
| B. | Ozone rays reduce greenhouse effect |
| C. | Ozone layer reflects radio waves |
| D. | Ozone layer controls \[{{O}_{2}}/{{H}_{2}}\] radio in atmosphere |
| Answer» B. Ozone rays reduce greenhouse effect | |
| 7138. |
Wave which cannot travel in vacuum is [MP PMT 1994] |
| A. | X-rays |
| B. | Infrasonic |
| C. | Ultraviolet |
| D. | Radiowaves |
| Answer» C. Ultraviolet | |
| 7139. |
Which of the following waves have the maximum wavelength [AFMC 2002] |
| A. | X-rays |
| B. | I.R. rays |
| C. | UV rays |
| D. | Radio waves |
| Answer» E. | |
| 7140. |
The ozone layer absorbs [Kerala PET 2002] |
| A. | Infrared radiations |
| B. | Ultraviolet radiations |
| C. | X-rays |
| D. | g-rays |
| Answer» C. X-rays | |
| 7141. |
The electromagnetic waves travel with a velocity [J & K CET 2002] |
| A. | Equal to velocity of sound |
| B. | Equal to velocity of light |
| C. | Less than velocity of light |
| D. | None of these |
| Answer» C. Less than velocity of light | |
| 7142. |
Ozone is found in [DPMT 2002] |
| A. | Stratosphere |
| B. | Ionosphere |
| C. | Mesosphere |
| D. | Troposphere |
| Answer» B. Ionosphere | |
| 7143. |
Which of the following radiations has the least wavelength [AIEEE 2003] |
| A. | g -rays |
| B. | b-rays |
| C. | a-rays |
| D. | X-rays |
| Answer» B. b-rays | |
| 7144. |
The speed of electromagnetic wave in vacuum depends upon the source of radiation [Kerala PMT 2004] |
| A. | Increases as we move from g-rays to radio waves |
| B. | Decreases as we move from g-rays to radio waves |
| C. | Is same for all of them |
| D. | None of these |
| Answer» D. None of these | |
| 7145. |
Which of the following statement is wrong [NCERT 1976] |
| A. | Infrared photon has more energy than the photon of visible light |
| B. | Photographic plates are sensitive to ultraviolet rays |
| C. | Photographic plates can be made sensitive to infrared rays |
| D. | Infrared rays are invisible but can cast shadows like visible light rays |
| Answer» B. Photographic plates are sensitive to ultraviolet rays | |
| 7146. |
Pick out the longest wavelength from the following types of radiations [CBSE PMT 1990] |
| A. | Blue light |
| B. | g-rays |
| C. | X-rays |
| D. | Red light |
| Answer» E. | |
| 7147. |
A charge is placed at the centre of the open end of cylindrical vessel. The flux of the electric field through the surface of the vessel is [MNR 1998] |
| A. | Zero |
| B. | |
| C. | |
| D. | |
| Answer» D. | |
| 7148. |
A point charge is placed at the centre of a cube of side . The electric flux emerging from the cube is [CBSE PMT 1996; BCECE 2003; AIEEE 2002] |
| A. | |
| B. | Zero |
| C. | |
| D. | |
| Answer» B. Zero | |
| 7149. |
Eight dipoles of charges of magnitude are placed inside a cube. The total electric flux coming out of the cube will be [MP PMT/PET 1998] |
| A. | |
| B. | |
| C. | |
| D. | Zero |
| Answer» E. | |
| 7150. |
A cube of side is placed in a uniform field , where . The net electric flux through the cube is [Haryana CEE 1996] |
| A. | Zero |
| B. | |
| C. | |
| D. | |
| Answer» B. | |