# Solved papers for NEET Physics EM Waves NEET PYQ-EM Waves

### done NEET PYQ-EM Waves Total Questions - 23

• question_answer1) Ozone layer blocks the radiations of wave length:                                                    [AIPMT 1999]

A)
less than $3\times {{10}^{-7}}\,m$

B)
equal to $3\times {{10}^{-7}}\,m$

C)
more than $3\times {{10}^{-7}}\,m$

D)
all of the above

• question_answer2) The wavelength of light of frequency 100 Hz is:                                                                  [AIPMT 1999]

A)
$2\times {{10}^{6}}m$

B)
3$3\times {{10}^{6}}m$

C)
$4\times {{10}^{6}}m$

D)
$5\times {{10}^{6}}m$

A)
a stationary charge

B)
uniformly moving charges

C)
accelerated charges

D)
all of the above

• question_answer4) The frequency of $\gamma -rays,$ X-rays and ultraviolet rays are a, b and c respectively. Then:

A)
$a>b>c$

B)
$a<b<c$

C)
$a=b=c$

D)
$a>c>b$

• question_answer5) Ozone layer in atmosphere is useful, because it:                                                                  [AIPMT 2001]

A)

B)
absorbs polluent gases

C)
stops green house effect

D)
stops increase in temperature of atmosphere

• question_answer6) What is the cause of "Greenhouse effect"?                                                                           [AIPMT 2002]

A)
Infrared rays

B)
Ultraviolet rays

C)
X-rays

D)

• question_answer7) The velocity of electromagnetic wave is along the direction of:                                [AIPMT 2002]

A)
$\vec{B}\times \vec{E}$

B)
$\vec{E}\times \vec{B}$

C)
$\vec{E}$

D)
$\vec{B}$

• question_answer8) Which of the following has minimum wavelength?                                                               [AIPMT 2002]

A)
X-rays

B)
Ultraviolet rays

C)
$\gamma$-rays

D)
Cosmic rays

• question_answer9) Which of the following rays are not electromagnetic waves?                                             [AIPMT 2003]

A)
$\beta$-rays

B)
Heat rays

C)
X-rays

D)
$\gamma$-rays

• question_answer10) We consider the radiation emitted by the human body. Which of the following statements is true?          [AIPMT 2003]

A)
The radiation is emitted during the summers and absorbed during the winters

B)
The radiation emitted lies in the ultraviolet region and hence is not visible

C)
The radiation emitted is in the infra-red region

D)
The radiation is emitted only during the day

• question_answer11) If ${{\lambda }_{v}},\,{{\lambda }_{x}}\,$ and ${{\lambda }_{m}}$ represent the wavelengths of visible light, X-rays and microwaves respectively, then:                                                                              [AIPMT (S) 2005]

A)
${{\lambda }_{m}}>{{\lambda }_{x}}>{{\lambda }_{v}}$

B)
${{\lambda }_{v}}>{{\lambda }_{m}}>{{\lambda }_{x}}$

C)
${{\lambda }_{m}}>{{\lambda }_{v}}>{{\lambda }_{x}}$

D)
${{\lambda }_{v}}>{{\lambda }_{x}}>{{\lambda }_{m}}$

• question_answer12) The electric and magnetic field of an electromagnetic wave are:                                   [AIPMT (S) 2007]

A)
in phase and parallel to each other

B)
in opposite phase and perpendicular to each other

C)
in opposite phase and parallel to each other

D)
in phase and perpendicular to each other

• question_answer13) The velocity of electromagnetic radiation in a medium of permittivity ${{\varepsilon }_{0}}$ and permeability ${{\mu }_{0}}$ is given by                                                                                             [AIPMPT (S) 2008]

A)
$\sqrt{\frac{{{\varepsilon }_{0}}}{{{\mu }_{0}}}}$

B)
$\sqrt{{{\mu }_{0}}{{\varepsilon }_{0}}}$

C)
$\frac{1}{\sqrt{{{\mu }_{0}}{{\varepsilon }_{0}}}}$

D)
$\sqrt{\frac{{{\mu }_{0}}}{{{\varepsilon }_{0}}}}$

• question_answer14)  The electric field of an electromagnetic wave in free space is given by $\overset{\to }{\mathop{\mathbf{E}}}\,=10\cos ({{10}^{7}}t+kx)\mathbf{\hat{j}}v/m,$ where t and x are in seconds and metres respectively. It can be inferred that                                                                        [AIPMT (M) 2010] (1) The wavelength $\lambda$ is 188.4 m. (2) The wave number k is 0.33 rad/m. (3) The wave amplitude is 10 V/m. (4) The wave is propagating along $+x$ direction Which one of the following pairs of statements is correct?

A)
(3) and (4)

B)
(1) and (2)

C)
(2) and (3)

D)
(1) and (3)

• question_answer15) The decreasing order of wavelength of infrared, microwave, ultraviolet and gamma rays is        [AIPMT (S) 2011]

A)
gamma   rays,   ultraviolet,   infrared, microwaves

B)
(b microwaves,   gamma   rays,   infrared, ultraviolet

C)
infrared, microwave, ultraviolet, gamma rays

D)
microwave infrared, ultraviolet, gamma rays

• question_answer16)  The dimensions of ${{({{\mu }_{0}}{{\varepsilon }_{0}})}^{-1/2}}$ are                        [AIPMT (M) 2012]

A)
$[{{L}^{1/2}}T{{-}^{1/2}}]$

B)
$[{{L}^{-1}}T]$

C)
$[L{{T}^{-1}}]$

D)
$[{{L}^{1/2}}{{T}^{1/2}}]$

• question_answer17) The ratio of amplitude of magnetic field to the amplitude of electric field for an electromagnetic  wave  propagating  in vacuum is equal to                                                                                                          [AIPMT (M) 2012]

A)
the speed of light in vacuum

B)
reciprocal of speed of light in vacuum

C)
the ratio of magnetic permeability to the electric susceptibility of vacuum

D)
unity

• question_answer18) The   condition   under which   a microwave oven heats up a food item containing water molecules most efficiently is                                                                                                                                          [NEET 2013]

A)
the frequency of the microwave must match the resonant frequency of the water molecules

B)
the frequency of the microwave has no relation with natural frequency of water molecules

C)
microwave are heat waves, so always produce heating

D)
infrared waves produce heating in a microwave oven

• question_answer19) The energy of the EM waves is of the order of $15\text{ }keV$. To which part of the spectrum does it belong?                                                                                                                                                   [NEET (Re) 2015]

A)
X-rays

B)
Infrared rays

C)
Ultravioiet rays

D)
$\gamma$-rays

• question_answer20) Out of the following options which one can be   used to produce a propagating electromagnetic wave?   [NEET - 2016]

A)
A charge moving at constant velocity

B)
A stationary charge

C)
A chargeless particle

D)
An accelerating charge

• question_answer21) In an electromagnetic wave in free space the root mean square value of the electric field is ${{E}_{rms}}=6\,V/m$. The peak value of the magnetic field is                                                                                            [NEET-2017]

A)
$4.23\times {{10}^{-8}}T$

B)
$1.41\times {{10}^{-8}}T$

C)
$2.83\times {{10}^{-8}}T$

D)
$0.70\times {{10}^{-8}}T$

• question_answer22) An em wave is propagating in a medium with a velocity $\overrightarrow{\text{v}}=\text{v}\widehat{\text{i}}$. The instantaneous oscillating electric field of this em wave is along $\text{+y}$ axis. Then the direction of oscillating magnetic field of the em wave will be along                                                                                [NEET - 2018]

A)
-y direction

B)
+z direction

C)
-z direction

D)
-x direction

• question_answer23) The ratio of contributions made by the electric field and magnetic field components to the intensity of an electromagnetic wave is: (c = speed of electromagnetic waves)                                            [NEET 2020]

A)
$1:1$

B)
$1:c$

C)
$1:{{c}^{2}}$

D)
$c:1$