Multiple Choice QuestionsWhich of the following electromagnetic waves have the smallest wavelength?
γ - rays
X- rays
UV waves
infrared rays
X-rays are used in determining the molecular structure of crystalline because
its energy is high
it can penetrate the material
its wavelength is comparable to interatomic distance
its frequency is low
C.
its wavelength is comparable to interatomic distance
Crystal structure is explored through the diffraction of waves having a wavelength comparable with the interatomic spacing ( 10-10 m) in crystals. Radiation of longer wavelength cannot resolve the details of structure, while radiation of much shorter wavelength is diffracted through in conveniently small angles. Usually diffraction of X-rays is employed in the study of crystal structure as X-rays have wavelength comparable to interatomic spacing.
Assertion: The electromagnetic waves are transverse in nature.
Reason: Waves of wavelength 10 µm are radiowave and microwave.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Assertion: UV radiation causes photodissociation of ozone into O2 and O, thus causing damage to the stratospheric ozone layer.
Reason: Ozone hole is resulting in global warming and climate change.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false
If both assertion and reason are false
Assertion: Electromagnetic waves with frequencies smaller than the critical frequencies of ionosphere cannot be used for communication using sky wave propagation.
Reason: The refractive index of the ionosphere becomes very high for frequencies higher than the critical frequency.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Assertion: Electromagnetic radiations exert pressure.
Reason: Electromagnetic-waves carry both momentum and energy.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
The frequency order for X-rays ( A), γ-rays (B), UV rays (C) is
B > A > C
A > B > C
C > B > A
A > C > B
Assertion: In electromagnetic waves electric field and magnetic field lines are perpendicular to each other.
Reason: Electric field and magnetic field are self sustaining.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Assertion: Electromagnetic waves are transverse in nature
Reason: The electric and magnetic fields of an e.m. wave are perpendicular to each other and also perpendicular to the direction of wave propogation.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Assertion: X-ray astronomy is possible only from satellites orbiting the earth.
Reason: Efficiency of X-rays telescope is large as compared to any other telescope.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
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