In Young’s double-slit experiment, an interference pattern is obtained on a screen by a light of wavelength 6000 Å, coming from the coherent sources S1 and S2. At certain point P on the screen third dark fringe is formed. Then the path difference S1P – S2P in microns is
|
(a) 0.75 |
(b) 1.5 |
(c) 3.0 |
(d) 4.5 |
(b) 1.5
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The wing span of an aeroplane is 20 metre. It is flying in a field, where the vertical component of magnetic field of earth is 5 × 10–5 tesla, with velocity 360 km/h. The potential difference produced between the blades will be
|
(a) 0.10 V |
(b) 0.15 V |
(c) 0.20 V |
(d) 0.30 V |
The effective resistance between points A and B is
|
(a) 10 Ω |
(b) 20 Ω |
|
(c) 40 Ω |
(d) None of the above three values |
The forbidden gap in the energy bands of germanium at room temperature is about
|
(a) 1.1 eV |
(b) 0.1 eV |
(c) 0.67 eV |
(d) 6.7 eV |
A particle moving in a magnetic field increases its velocity, then its radius of the circle
|
(a) Decreases |
(b) Increases |
(c) Remains the same |
(d) Becomes half |
The maximum focal length of the eye-lens of a person is greater than its distance from the retina. The eye is: