CBSE
Multiple Choice QuestionsAn electromagnetic wave travels along Z- axis. The pair of space and time varying field is
Ey, Bx
By, Ez
Ex, By
Ez, Bx
Spectrum of a star is shifting towards voilet colour, then the star
is going away from earth
is coming towards earth
intensity of light of star is increasing
intensity of light of star is decreasing
Light waves of wavelength is incident on a metal of work function . Maximum velocity of the electron is :
The energy of an X-ray photon is 2 keV, then its frequency will be
3.2 x 10-6 per second
5 x 1017 per second
2 x 1017 per second
2 × 1018 per second
The speed of electromagnetic waves in vaccum is
µ0ε0
An electron beam is accelerated through a potential difference of V volt. The minimum wavelength of X-rays produced is :
The nature of light waves is similar to
cosmic rays
cathode rays
gamma rays
alpha rays
The minimum wavelength of X-ray emitted by X-ray tube is 0.4125 . The accelerating voltage is
30 kV
50 kV
80 kV
60 kV
X-rays are not used for radar purposes because they are not
reflected by target
partly absorbed by target
electromagnetic waves
completely absorbed by target
Arrange the following electromagnetic radiation in the order of decreasing energy.
A. Infrared waves B. Ultraviolet rays
C. Orange light D. Green light
B, C, A, D
D, A, C, B
B, D, C, A
A, C, D, B
