In case of a semiconductor, which of the following statement is wrong
|
(a) Doping increases conductivity |
|
(b) Temperature coefficient of resistance is negative |
|
(c) Resisitivity is in between that of a conductor and insulator |
|
(d) At absolute zero temperature, it behaves like a conductor |
(d) At absolute zero temperature, it behaves like a conductor
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In X-ray spectrum wavelength 
of line 
depends on atomic number Z as
|
(a) |
(b) |
(c) |
(d) |
Electric lines of force about negative point charge are
|
(a) Circular, anticlockwise |
(b) Circular, clockwise |
|
(c) Radial, inward |
(d) Radial, outward |
Two nucleons are at a separation of 1 
. The net force between them is 
, if both are neutrons, 
if both are protons and 
if one is a proton and other is a neutron. In such a case
|
(a) |
(b) |
(c) |
(d) |
The ionisation energy of 10 times ionised sodium atom is
|
(a) 13.6 eV |
(b) 13.6 × 11 eV |
(c) |
(d) 13.6 × (11)2 eV |
If the current is doubled, the deflection is also doubled in
|
(a) A tangent galvanometer |
(b) A moving coil galvanometer |
|
(c) Both (a) and (b) |
(d) None of these |
A parallel plate condenser with oil between the plates (dielectric constant of oil K = 2) has a capacitance C. If the oil is removed, then capacitance of the capacitor becomes
|
(a) |
(b) 2C |
(c) |
(d) |
A point charge +q is placed at the centre of a cube of side L. The electric flux emerging from the cube is
|
(a) |
(b) Zero |
(c) |
(d) |
In the figure is shown Young’s double slit experiment. Q is the position of the first bright fringe on the right side of O. P is the 11th fringe on the other side, as measured from Q. If the wavelength of the light used is 6000 
, then 
will be equal to
|
(a) 6 |
(b) 6.6 |
(c) 3.138 |
(d) 3.144 |
During mean life of a radioactive element, the fraction that disintegrates is
|
(a) e |
(b) |
(c) |
(d) |
