In a material medium, when a positron meets an electron both the particles annihilate leading to the emission of two gamma ray photons. This process forms the basis of an important diagnostic procedure called
|
(a) MRI |
(b) PET |
(c) CAT |
(d) SPECT |
(b) PET
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Focal length of a plane mirror is
|
(a) Zero |
(b) Infinite |
(c) Very less |
(d) Indefinite |
A photon of wavelength 4400 Å is passing through vacuum. The effective mass and momentum of the photon are respectively
|
(a) 5 |
(b) 5 |
|
(c) Zero, 1.5 |
(d) 5 |
In electrolysis, if the duration of the passage of current is doubled, the mass liberated i
|
(a) Doubled |
(b) Halved |
(c) Increased four times |
(d) Remains the same |
In which of the following is the interference due to the division of wave front
|
(a) Young's double slit experiment |
(b) Fresnel's biprism experiment |
|
(c) Lloyd's mirror experiment |
(d) Demonstration colours of thin film |
For a medium, refractive indices for violet, red and yellow are 1.62, 1.52 and 1.55 respectively, then dispersive power of medium will be
|
(a) 0.65 |
(b) 0.22 |
(c) 0.18 |
(d) 0.02 |
The work function for tungsten and sodium are 4.5 eV and 2.3 eV respectively. If the threshold wavelength λ for sodium is 
, the value of λ for tungsten is
|
(a) 5893 Å |
(b) 10683 Å |
(c) 2791 Å |
(d) 528 Å |
