Three resistances of one ohm each are connected in parallel. Such connection is again connected with 2/3 Ω resistor in series. The resultant resistance will be
|
(a) |
(b) |
(c) 1 Ω |
(d) |
(c) 1 Ω
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Four charges equal to – Q are placed at the four corners of a square and a charge q is at its centre. If the system is in equilibrium the value of q is
|
(a) |
(b) |
(c) - |
(d) |
The mechanism of the heat produced in a conductor when an electric current flows through it, can be explained on the basis of
|
(a) Viscosity |
(b) Friction |
(c) Free electron theory |
(d) Gauss's theorem |
The stopping potential (
versus frequency (n) plot of a substance is shown in figure the threshold wave length is
|
(a) 5 |
(b) 6000Å |
|
(c) 5000 Å |
(d) Can not be estimated from given data |
Angle of a prism is 30° and its refractive index is 
and one of the surface is silvered. At what angle of incidence, a ray should be incident on one surface so that after reflection from the silvered surface, it retraces its path
|
(a) 30° |
(b) 60° |
(c) 45° |
(d) |
When unpolarised light beam is incident from air onto glass (n = 1.5) at the polarising angle
|
(a) Reflected beam is polarised 100 percent |
|
(b) Reflected and refracted beams are partially polarised |
|
(c) The reason for (a) is that almost all the light is reflected |
|
(d) All of the above |
