| 1 |
Pure form of semiconductor is called |
Extrinsic semiconductor
Intrinsic semiconductor
N type
P type material
|
| 2 |
A valance band in solids is |
Always completely filled
Empty
Either completely or partially filled
None
|
| 3 |
The electrons in the outermost shell are called |
Super electrons
Valance electrons
Full valance
Upper deep up
|
| 4 |
Conductivity of semiconductor is of order of |
10<sup>-6</sup> to 10<sup>4</sup> Ω<sup>-1</sup> m<sup>-1</sup>
10<sup>-10</sup> to 10<sup>-20</sup> (Ωm)<sup>-1</sup>
10<sup>7</sup> Ωm<sup>-1</sup>
None
|
| 5 |
Such substances which break soon after they cross elastic limit is called |
Weak substance
Ductile substance
Brittle substance
Organic substance
|
| 6 |
The SI unit of stress is same as that of |
Momentum
Pressure
Force
Length
|
| 7 |
The ability of body to return to its original shape is called |
Elasticity
Stress
Strain
Shear
|
| 8 |
Which one of the following is polymer |
Polythene
Polystyrene
Nylon
All
|
| 9 |
Amorphous solids are called |
Polymeric
Crystal
Glassy solids
All
|
| 10 |
The idea that all magnetic effects may be due to circulating currents (i.e moving charges) Was first held by |
Ampere
Faraday
Lenz
Gauss
|
| 11 |
When a germanium atom is doped with phosphorous atoms it becomes |
N-type semiconductor
p-type semiconductor
An insulator
None of them
|
| 12 |
Acceptor impurities donate |
Holes
Electrons
Both Electrons and Holes
None of them
|
| 13 |
Donor impurities donate |
Holes
Electrons
Both holes and electrons
None of them
|
| 14 |
An n-type semiconductor is obtained by doping germanium or silicon with |
Tetravalent impurity
Trivalent impurity
Pentavalent impurity
Monovalent inpurity
|
| 15 |
The charged nucleus of an atom itself spins its magnetic field is |
Equal to the field produced by orbital electrons
Greater than the field produced by orbital electrons
Much weaker than the field produced by orbital electrons
Very strong
|
| 16 |
The greatest stress that a material can endure without losing the proportionality between stress and strain is called |
Plasticity
Breaking point
Proportional limit
Strain
|
| 17 |
In the stress-strain graph stress is increased linearly with strain until a point is reached this point is known as |
Plastic limit
Plastic deformation
Proportional limit
Elastic behaviour
|
| 18 |
Ratio between total intensity of magnetic field at equator to poles is |
1 : 1
2 : 1
1 : 2
1 : 4
|
| 19 |
The conductivity of super conductor at critical temperature becomes |
Zero
1
Infinite
Negative
|
| 20 |
The unit cell of the shape of match box is called |
Cubic
Tetragonal
Orthorhombic
Rhomboheral
|
| 21 |
Which of the following is not true for a crystalline substance |
Shorter range order
Isotropic electrical conductivity
Flat surface
Sharp melting point
|
| 22 |
The young s modulus for a perfectly rigid body is |
Zero
1
Infinite
None of these
|
| 23 |
A wire is stretched by applying a stretching force.If the stretching force is doubled within elastic limit Then energy stored in the wire will |
Be double
Increase by four times
Increase by eight time
Remain same
|
| 24 |
A women of 50 kg distributes her wright equally over high-heeld shoes. Each heel has an area of 0.75 cm2. The pressure exerted by each heel will be |
6.66 x 10<sup>6</sup> Pa
3.33 x 10<sup>6</sup> Pa
1.67 x 10<sup>6</sup> Pa
3.33 x 10<sup>-6</sup> Pa
|
| 25 |
The limit up to which the stress is directly proportional to strain is called |
Elastic limit
Proportional limit
Breaking limit
Ultimate tensile limit
|
| 26 |
If the tensile force is suddenly removed from a wire then its temperature will |
Decrease
Increase
Becomes zero
Remain constant
|
| 27 |
In compound microscope image formed is |
Real erect and diminished
Virtual inverted magnitude
Real inverted and magnified
Virtual inverted and magnified
|
| 28 |
Spectrometer can be used to |
Measure wave length of light
Measure refractive index of the materials
Study spectra of light
All
|
| 29 |
Optical device used in spectrometer |
Simple microscope
Compound microscope
Telescope
Any of them
|
| 30 |
Basic principle of an optical fibre is |
Reflection
Scattering
Polarization
Total internal reflection
|
| 31 |
The index of refraction of diamond is 2.0 velocity of light in diamond in m/s is |
6 x 10<sup>8</sup>
3 x 10<sup>8</sup>
2 x 10<sup>8</sup>
1.5 x 10<sup>8</sup>
|
| 32 |
The cause of power loss in optic fibre is |
Absorption
Scattering
Dispersion
All
|
| 33 |
Source of light used in the fibre optic communication |
Led
Laser
Photo diode
Both a and b
|
| 34 |
An object is placed at a distance of 200 cm from a convex lens of focal length 10 cm the linear magnification is |
1/3
2/3
3/4
None
|
| 35 |
In compound microscope magnification of objective is 2 and magnification of eyepiece is 4 magnification of compound microscope is |
2
6
8
None
|
| 36 |
A telescope has an objective of focal length 10 cm the magnifying power of telescope is 5.Its length in normal adjustment is |
7.5cm
10.5 cm
12 cm
15 cm
|
| 37 |
A convex lens of focal length 5 cm is used as magnifying glass Its magnifying power when the image is formed at infinity |
6
5
1.5
7
|
| 38 |
Which does not show polarization |
Longitudinal wave in gas
Transverse wave in gas
Both a and b
None of these
|
| 39 |
Which of the following is conserved when light waves interfere |
Intensity
Energy
Amplitude
Momentum
|
| 40 |
Inverse square law for luminace is valid for |
Search light
Isotropic point source
Cylindrical source
All types of source
|