A double charged lithium atom is equivalent to hydrogen whose atomic number is 3. The wavelength of required radiation for emitting electron from first to third Bohr orbit in 
will be (Ionisation energy of hydrogen atom is 13.6eV)
|
(a) 182.51 Å |
(b) 177.17 Å |
(c) 142.25 Å |
(d) 113.74 Å |
(d) 113.74 Å
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A small lamp is hung at a height of 8 feet above the centre of a round table of diameter 16 feet. The ratio of intensities of illumination at the centre and at points on the circumference of the table will be
|
(a) 1 : 1 |
(b) 2 : 1 |
(c) 2 |
(d) 3 : 2 |
In an induction coil, the secondary e.m.f. is
|
(a) Zero during break of the circuit |
|
(b) Very high during make of the circuit |
|
(c) Zero during make of the circuit |
|
(d) Very high during break of the circuit |
The k line of singly ionised calcium has a wavelength of 393.3 nm as measured on earth. In the spectrum of one of the observed galaxies, this spectral line is located at 401.8 nm. The speed with which the galaxy is moving away from us, will be
|
(a) 6480 km/s |
(b) 3240 km/s |
(c) 4240 km/sec |
(d) None of these |
Two slits are separated by a distance of 0.5 mm and illuminated with light of λ = 6000 Å. If the screen is placed 2.5 m from the slits. The distance of the third bright image from the centre will be
|
(a) 1.5 mm |
(b) 3 mm |
(c) 6 mm |
(d) 9 mm |
The bit rate for a signal, which has a sampling rate of 8 kHz and where 16 quantisation levels have been used is
|
(a) 32000 bits/sec |
(b) 16000 bits/sec |
(c) 64000 bits/sec |
(d) 72000 bits/sec |
