The phase difference between incident wave and reflected wave is 180° when light ray
|
(a) Enters into glass from air |
(b) Enters into air from glass |
|
(c) Enters into glass from diamond |
(d) Enters into water from glass |
(a) Enters into glass from air
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For germanium crystal, the forbidden energy gap in joules is
|
(a) 1.12 |
(b) 1.76 |
(c) 1.6 |
(d) Zero |
When air is replaced by a dielectric medium of constant k, the maximum force of attraction between two charges separated by a distance
|
(a) Decreases k times |
(b) Remains unchanged |
|
(c) Increases k times |
(d) Increases |
Dark lines on solar spectrum are due to
|
(a) Lack of certain elements |
|
(b) Black body radiation |
|
(c) Absorption of certain wavelengths by outer layers |
|
(d) Scattering |
An electron passing through a potential difference of 4.9 V collides with a mercury atom and transfers it to the first excited state. What is the wavelength of a photon corresponding to the transition of the mercury atom to its normal state
|
(a) 2050 Å |
(b) 2240 Å |
(c) 2525 Å |
(d) 2935 Å |
The energy of electron in the nth orbit of hydrogen atom is expressed as 
. The shortest and longest wavelength of Lyman series will be
| (a) 910 Å, 1213 Å | (b) 5463 Å, 7858 Å | (c) 1315 Å, 1530 Å | (d) None of these |
The focal length of the objective lens of a compound microscope is
|
(a) Equal to the focal length of its eye piece |
|
(b) Less than the focal length of eye piece |
|
(c) Greater than the focal length of eye piece |
|
(d) Any of the above three |
