In a two slit experiment with monochromatic light fringes are obtained on a screen placed at some distance from the sits. If the screen is moved by 5 
towards the slits, the change in fringe width is 3 
. If separation between the slits is 
, the wavelength of light used is
|
(a) 6000 Å |
(b) 5000 Å |
(c) 3000 Å |
(d) 4500 Å |
(a) 6000 Å
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The contribution in the total current flowing through a semiconductor due to electrons and holes are 
and 
respectively. If the drift velocity of electrons is 
times that of holes at this temperature, then the ratio of concentration of electrons and holes is
|
(a) 6 : 5 |
(b) 5 : 6 |
(c) 3 : 2 |
(d) 2 : 3 |
A simple microscope has:
Which one of the series of hydrogen spectrum is in the visible region
|
(a) Lyman series |
(b) Balmer series |
(c) Paschen series |
(d) Bracket series |
Two small spheres each having the charge +Q are suspended by insulating threads of length L from a hook. This arrangement is taken in space where there is no gravitational effect, then the angle between the two suspensions and the tension in each will be
|
(a) 180°, |
(b) 90°, |
(c) 180°, |
(d) 180°, |
Select the correct alternative, The angle between the normal and refracted ray is called:
The activity of a radioactive sample
|
(a) Can be increased by heating it |
(b) Is independent of physical parameter |
|
(c) Cannot be increased by any method |
(d) Both (b) and (c) |
