The photoelectric threshold wavelength for a metal surface is 6600 Å. The work function for this is
|
(a) 1.87 V |
(b) 1.87 eV |
(c) 18.7 eV |
(d) 0.18 eV |
(b) 1.87 eV
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Dual nature of radiation is shown by
|
(a) Diffraction and reflection |
(b) Refraction and diffraction |
|
(c) Photoelectric effect alone |
(d) Photoelectric effect and diffraction |
In a P-type semi-conductor, germanium is dopped with
|
(a) Gallium |
(b) Boron |
(c) Aluminium |
(d) All of these |
Glass has refractive index m with respect to air and the critical angle for a ray of light going from glass to air is q. If a ray of light is incident from air on the glass with angle of incidence q, the corresponding angle of refraction is
|
(a) |
(b) 90° |
(c) |
(d) |
Charges q, 2q, 3q and 4q are placed at the corners A, B, C and D of a square as shown in the following figure. The direction of electric field at the centre of the square is along
|
(a) AB |
(b) CB |
(c) BD |
(d) AC |
The splitting of white light into several colours on passing through a glass prism is due to
|
(a) Refraction |
(b) Reflection |
(c) Interference |
(d) Diffraction |
Water of volume 2 litre in a container is heated with a coil of 1 kW at 27 oC. The lid of the container is open and energy dissipates at rate of 160 J/s. In how much time temperature will rise from 27oC to 77oC [Given specific heat of water is 4.2 kJ/kg]
|
(a) 8 min 20 s |
(b) 6 min 2 s |
(c) 7 min |
(d) 14 min |
