A solid conducting sphere of radius a has a net positive charge 2Q. A conducting spherical shell of inner radius b and outer radius c is concentric with the solid sphere and has a net charge – Q. The surface charge density on the inner and outer surfaces of the spherical shell will be
|
(a) |
(b) |
(c) 0, |
(d) None of the above |
(a) 
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An oil drop having charge 2e is kept stationary between two parallel horizontal plates 2.0 cm apart when a potential difference of 12000 volts is applied between them. If the density of oil is 900 kg/m3, the radius of the drop will be
|
(a) 2.0 |
(b) 1.7 |
(c) 1.4 |
(d) 1.1 |
A polariser is used to
|
(a) Reduce intensity of light |
(b) Produce polarised light |
|
(c) Increase intensity of light |
(d) Produce unpolarised light |
If the work function for a certain metal is 3.2 
joule and it is illuminated with light of frequency 8 
Hz. The maximum kinetic energy of the photo-electrons would be (h = 6.63 
|
(a) 3.2 |
(b) 8.5 |
(c) 5.3 |
(d) 3.2 |
The production of e.m.f. by maintaining a difference of temperature between the two junctions of two different metals is known as
|
(a) Joule effect |
(b) Seebeck effect |
(c) Peltier effect |
(d) Thomson effect |
The attenuation in optical fibre is mainly due to
|
(a) Absorption |
(b) Scattering |
|
(c) Neither absorption nor scattering |
(d) Both (a) and (b) |
An electron of mass m when accelerated through a potential difference V has de-Broglie wavelength λ. The de-Broglie wavelength associated with a proton of mass M accelerated through the same potential difference will be
|
(a) λ |
(b) λ |
(c) λ |
(d) λ |
For a nucleus to be stable, the correct relation between neutron number N and Proton number Z is
|
(a) N > Z |
(b) N = Z |
(c) N < Z |
(d) N ≥ Z |
