The central fringe will be white.
There will not be a completely dark fringe.
The fringe next to the central will be violet.
Explanation:
The superposition of all the colours at the central maxima gives the central band a white colour. As we go from the centre to corner, the fringe colour goes from violet to red. There will not be a completely dark fringe, as complete destructive interference does not take place.
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The wavelength of the energy emitted when electron come from fourth orbit to second orbit in hydrogen is 20.397 cm. The wavelength of energy for the same transition in 
is
|
(a) |
(b) |
(c) |
(d) |
A circular metal plate of radius R is rotating with a uniform angular velocity ω with its plane perpendicular to a uniform magnetic field B. Then the emf developed between the centre and the rim of the plate is
|
(a) πω |
(b) ω |
(c) πω |
(d) ω |
Two capacitors each of capacity 2 μF are connected in parallel. This system is connected in series with a third capacitor of 12 μF capacity. The equivalent capacity of the system will be
|
(a) 16 μF |
(b) 13 μF |
(c) 4 μF |
(d) 3 μF |
If the mass number of an atom is A = 40 and its electron configuration is 
, the number of neutrons and protons in its nucleus will be
| (a) 22, 18 | (b) 18, 22 |
(c) 20, 20 |
(d) 18, 18 |
