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CBSE Questions for Class 12 Medical Physics Electromagnetic Waves Quiz 5 - MCQExams.com

Two waves having same velocity enter electric and magnetic fields respectively. If λ1andλ2 are their wavelengths as they move in the fields, then
  • λ1,λ2 are constants
  • λ1 and λ2 are variable
  • λ1 is variable λ2 is constant
  • λ2 is variable, λ1 is constant
We consider the radiation emitted by the human body. Which of the following statements is true :
  • The radiation emitted is in the infrared region
  • The radiation is emitted only during the day
  • The radiation is emitted during the summers and absorbed during the winters
  • The radiation emitted lies in the ultraviolet region and hence is not visible
PAR range of wavelength is 
  • 400700nm
  • 400800nm
  • 450950nm
  • 500600nm
Wave length of X-rays is
  • 1 A to 10 A
  • 0.01 A to 100 A
  • 0.001 A to 1 A
  • 0.1 A to 1 A
Which of the following relations is correct for electromagnetic waves:
  • 2Ex2=1c22Et2
  • 2Ex2=(Et)2
  • 2Ex2=c22Et2
  • 2Ex2=c2Et2
In which colour an yellow coloured dress would appear when viewed through a blue filter?
  • yellow
  • blue
  • black
  • green
The solar spectrum in general is:
  • radiation spectrum
  • absorption spectrum
  • emission spectrum
  • continuous spectrum
Radio isotope useful in treating blood cancer is
  • Cobalt 40
  • Carbon 60
  • Cobalt 60
  • Carbon 14
Wave length of visible spectrum extends from
  • 0.4 μ m- 0.7 μm
  • 0.5 nm - 6 nm
  • 5 μ m - 60 μm
  • 50 nm - 60 nm
Which of the following are produced by the high-frequency electromagnetic oscillators in electric circuits.
  • Microwaves
  • Longitudinal waves
  • Magnetic waves
  • None of these
Consider the radiations emitted by the human body. Which of the  following statements is true?
  • radiations lie in ultraviolet region
  • radiations lie in infrared region
  • radiations are emitted only during the day
  • radiations are emitted during summer and absorbed during winter
The method of using radio waves to cure some diseases are called
  • Physiotherapy
  • Netratherapy
  • Radiotherapy
  • Radiometry
If we denote microwaves, X rays, infrared, gamma rays, ultra-violet, radio waves and visible parts of the electromagnetic spectrum by M, X, I, G, U, R and V, the following is the arrangement in ascending order of wavelength :
  • R, M, I, V, U, X and G
  • M, R, V, X, U, G and I
  • G, X, U, V, I, M and R
  • I, M, R, U, V, X and G
If λv,λx,λm represents the wavelengths of vision, X-ray and microwaves respectively then
  • λm>λx>λv
  • λm>λv>λx
  • λv>λx>λm
  • λv>λm>λx
A parallel plate capacitor consists of two circular plates each of radius 12cm and separated by 5.0mm. The capacitor is being charged by an external source. The charging current is constant and is equal to 0.15A
The displacement current is:
  • 15A
  • 1.5A
  • 0.15A
  • 0.015A
The AM range of radiowaves has frequency:
  • less than 30MHz
  • more than 30MHz
  • less than 20000Hz
  • more than 20000Hz
The charge on a parallel plate capacitor is varying as q=q0sin(2πnt). The plates are very large and close together. neglecting the edge effects, the displacement current through the capacitor is:
  • qε0A
  • q0ε0sin2πnt
  • 2πnq0cos2πnt
  • 2πnq0ε0cos2πnt
The rms value of conduction current will be:
  • 5.7μA
  • 6.3μA
  • 9.6μA
  • 6.9μA
If the frequencies of an ultrasonic wave and an electromagnetic wave are same, then:
  • their wavelength will be same
  • wavelength of electromagnetic wave will be less than that of ultrasonic wave
  • wavelength of electromagnetic wave will be more than that of ultrasonic wave
  • the wavelengths of both will be nearly equal
Maxwell's four equations are written as
(i) E.ds=q0ε0
(ii)B.ds=0
(iii)E.dl=ddtB.ds
(iv)B.ds=μ0ε0ddtE.ds
Which of the above Maxwell's equations shows that electric field lines do not form closed loops?
  • (i) only
  • (ii) only
  • (iii) only
  • (iv) only
The Sun delivers 103W/m2 of electromagnetic flux to the Earth's surface. The radiation force on the roof of dimensions 8m×20m will be:
  • 3.33×105N
  • 5.33×104N
  • 7.33×103N
  • 9.33×102N
For treating arthritis
  • radio waves are used
  • direct current is used
  • mircowaves are used
  • AC of high  frequency is used
Maxwell's four equations are written as
(i) E.ds=q0ε0
(ii)B.ds=0
(iii)E.dl=ddtB.ds
(iv)B.ds=μ0ε0ddtE.ds
Out of the four Maxwell's equation above, which one shows the non-existence of monopoles?
  • (i) and (iv)
  • (ii) only
  • (iii) only
  • none of these
Instantaneous displacement current 1A in the space between the parallel plates of 1μF capacitor can be established by changing the potential difference at the rate of:
  • 0.1V/s
  • 1V/s
  • 106V/s
  • 106V/s
Assume you are sitting in sun for 2.5 hours. The area of your body exposed normally to sun rays 1.3m2. The intensity of sun rays is 1.1 Kilowatt/m2. If your body completely absorbs the sun rays then the momentum transferred to your body will be (in Kg-m/s):
  • 0.043
  • 0.037
  • 0.61
  • 0.91
The wavelengths for the light of red and blue colours are roughly 7.8×107m and 4.8×107m respectively. Which colour has the greater speed in vacuum?
  • Red
  • Violet
  • Yellow
  • All colors have same speed
For the propagation of electromagnetic waves
  • Medium is required
  • no medium is required
  • E and B are in mutually opposite phase
  • E and b do not contriute
Name the radiations of wavelength just shorter than 4×107m.
  • Infraviolet
  • Ultraviolet
  • Infrared
  • Ultrared
Arrange the following radiations in the order of their increasing wavelength:
X-rays, infra red rays, radio waves, gamma rays and micro waves.
  • Gamma rays, X-rays, infra red rays, radio waves, micro waves.
  • Gamma rays, micro waves, X-rays, infra red rays, radio waves.
  • Gamma rays, infra red rays, X-rays, micro waves, radio waves.
  • Gamma rays, X-rays, infra red rays, micro waves, radio waves.
Name the radiation which can be detected by a thermophile.
  • infrared radiation
  • ultraviolet radiation
  • X-rays
  • All of the above
Give the range of wavelength of the electromagnetic waves visible to us.
  • 1000Ao to 4000Ao
  • 4000Ao to 7000Ao
  • 8000Ao to 9000Ao
  • 400Ao to 800Ao
A wave has wavelength 50Ao. Which of the following is a use of this wave?
  • in detection of fracture in bones.
  • in detection of planets
  • in detection of water
  • in detection of air
A wave has a wavelength of 0.01A^o. Name the wave:
  • X rays
  • Micro waves
  • Gamma waves
  • Radio waves
A wave has wavelength 50A^o. State the speed of wave in vacuum.
  • 3\times 10^8ms^{-1}
  • >3\times 10^8ms^{-1}
  • <3\times 10^8ms^{-1}
  • Insufficient information
When light propagates in vaccum there is an electric field and a magnetic field. Which of the following is not true about these field?
  • They are constant in time
  • They have zero average value
  • They are perpendicular to the direction of propagation of light
  • They are mutually perpendicular
Name the rays or waves used for taking photographs in dark.
  • Infrared rays
  • Ultraviolet rays
  • X-rays
  • Gamma rays
A radiation A is focused by a proper device on the bulb of a thermometer. Mercury in the thermometer shows a rapid increase. The radiation A is:
  • infrared radiation
  • visible light
  • ultraviolet radiation
  • X-rays
Name the rays or waves produced by the changes in the nucleus of an atom.
  • X-rays
  • UV rays
  • Gamma rays
  • IR rays
An electromagnetic wave has a frequency of 500MHz and a wavelength of 60cm. Name the medium through which it is traveling.
  • air
  • water
  • salt
  • cardboard
In the propagation of light waves, the angle between the plane of vibration &  plane of polarisation is:
  • 0^0
  • 90^0
  • 45^0
  • 80^0
Read the following statements.
a. Ozone in found mostly in the stratosphere.
b. Ozone layer lies 55-75 kms above the surface of the earth.
c. Ozone absorbs ultraviolet radiation from the Sun.
d. Ozone layer has no significance for life on the earth.
Which set of the statements is correct ?
  • a and c
  • b and d
  • b and c
  • a and d
High energetic radiations among the following:
  • \lambda=0.01 A
  • \lambda=0.10 A
  • \lambda=1.00 A
  • \lambda=40.0 A
On the basis of the following features identify correct option:
I. They require no material medium.
II. They are always transverse.
II. They are produced by accelerating charged particles
  • Mechanical waves
  • Electro-magnetic waves
  • Both (1) and (2)
  • Neither (1) and (2)
Two waves A and B have wavelength 0.01A^o and 9000A^o respectively. Compare the speeds of these waves when they travel in vacuum.
  • 1:9
  • 9:1
  • 1:1
  • None of the above
Which of the following is the infrared wavelength?
  • {10}^{-4}\:cm
  • {10}^{-5}\:cm
  • {10}^{-6}\:cm
  • {10}^{-7}\:cm
Maxwell's modified form of Ampere's circuital law is
  • \displaystyle\oint_{\displaystyle s}{\vec{B}.\vec{ds}}=0
  • \displaystyle\oint_{\displaystyle s}{\vec{B}.\vec{dl}}=\mu_0I
  • \displaystyle\oint_{\displaystyle s}{\vec{B}.\vec{dl}}=\mu_0I+\frac{I}{\varepsilon_o}\frac{dq}{dt}
  • \displaystyle\oint_{\displaystyle s}{\vec{B}.\vec{dl}}=\mu_0I+\mu_0\varepsilon_o\frac{d\phi_E}{dt}
All components of the electromagnetic spectrum in vacuum have the same
  • energy
  • velocity
  • wavelength
  • frequency
The range of wavelength of visible light is:
  • 10\mathring{A} to 100\mathring{A}
  • 4000\mathring{A} to 7000\mathring{A}
  • 8000\mathring{A} to 10,000\mathring{A}
  • 10,000\mathring{A} to 15,000\mathring{A}
The displacement current is 
  • \displaystyle\varepsilon_o\frac{d\phi_E}{dt}
  • \displaystyle\frac{\varepsilon_o}{R}\frac{d\phi_E}{dt}
  • \displaystyle\varepsilon_o\frac{E}{R}
  • \displaystyle\varepsilon_oq\frac{C}{R}
If a source is transmitting an electromagnetic wave of frequency 8.2\times{10}^6\:Hz, then the wavelength of the electromagnetic waves transmitted from the source will be:
  • 36.6\ m
  • 40.5\ m
  • 42.3\ m
  • 50.9\ m
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