If cathode rays are projected at right angles to a magnetic field, their trajectory is
|
(a) Ellipse |
(b) Circle |
(c) Parabola |
(d) None of these |
(b) Circle
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Two infinite plane parallel sheets separated by a distance d have equal and opposite uniform charge densities σ. Electric field at a point between the sheets is
|
(a) Zero |
(b) |
|
(c) |
(d) Depends upon the location of the point |
The grid voltage of any triode valve is changed from –1 volt to – 3 volt and the mutual conductance is 3 
mho. The change in plate circuit current will be
|
(a) 0.8 mA |
(b) 0.6 mA |
(c) 0.4 mA |
(d) 1 mA |
To deposit one litre of hydrogen at 22.4 atmosphere from acidulaled water, the quantity of electricity that must pass through is
|
(a) 1 coulomb |
(b) 22.4 coulomb
|
(c) 96500 coulomb |
(d) 193000 coulomb |
In which frequency range, space waves are normally propagated
|
(a) HF |
(b) VHF |
(c) UHF |
(d) SHF |
There are certain material developed in laboratories which have a negative refractive index (Fig). A ray incident from air (medium 1) into such a medium (medium 2) shall follow a path given by:
A beam of monochromatic blue light of wavelength 4200Å in air travels in water (μ = 4/3). Its wavelength in water will be
|
(a) 2800 Å |
(b) 5600 Å |
(c) 3150 Å |
(d) 4000 Å |
In a dark room of photography, generally red light is used. The reason is
|
(a) Most of the photographic films are not sensitive to red light |
|
(b) The frequency for red light is low and hence the energy hv of photons is less |
|
(c) (a) and (b) both |
|
(d) None of the above |
