1.what is the process of producing electric dipole inside the dielectric by an external electric field is?
a) Polarizaion
b) Dipale monent
c) Susceptibility
(d) Magnetization
2.When does a diclectric become a conductor?
(a) At high temperalure
(b) In the presence of magnetic field
c) At avalanche breakdown
d) At dieloctric breakdown
3.Relation betwen B and H is
(a) B=uh
(b) B=uo(M+H)
(c) B=ur uo H
(d) All above
4.The phase velocily is given by
(a) Vph = Csquare/v
(b) Vph= dw/dk
(c) vph= v
(d) none of the above
5.For an electron accelerated through 10kV potential difference, the de Broglie wavelength is
(a) 1.226nm
(b) 0.01226nm
(c) 122.6nm
(d) 0.126nm
6.If free eleciron exists in a nucleus, it mist have a minimum energy of about
(a) 4Mev
(b) 9Mev
(c) 9kev
(d) 10 kev
7.1f the Zero point energy of a particle in an one dimensional potential of infinite height is IeV, then the energy of the second excited state is given by
(a) 2 eV
(b) 4 ev
(c)6 ev
(d) 9 eV
8.A plane intercepts at a, b/2, 2c. in a simple cubic unit cell. The miller indices of the plane are
a (214)
b) (241)
c)(421)
d) (124)
9.The Miller indices af the plane parallel to x and y axes are
a) (100)
b) (010)
c)(001)
d)(111)
10.In a Brage's spoctrometer for every rotation (teta) of the turn table the ionization chamber turns by an angle
a)teta
b)2teta
c)3teta
d)4teta
Answers
Answer:
1 magnetization
2 in the presence of magnetic field
3 all above
4 none of the above
5 0.01 226 nm
6 10k EV
7 9 ev
8 124
9 111
10 4 teta
Explanation:
Answer:
1.a 2.d 3.a 4.d 5.c 6.19.6 MeV
Explanation:
1. The process of producing electric dipoles inside the dielectrics by an external electric field is called polarisation.
2. When a dielectric is placed in an electric field and is increased, when the electric field exceeds the critical field, the dielectric loses its insulating property and becomes conducting. This is called dielectric breakdown.
3. Magnetic field strength and field intensity (H) is the amount of magnetizing force. Magnetic flux density (B) is the amount of magnetic force induced on the body due to the magnetizing force H. The relation between B and H is, B = μH.
4. The phase velocity is given by Vp = c cos θ. By substituting for cos θ = 2.5 and the speed of light, we get the phase velocity as 7.5 x 108 m/s. 3. The cut-off wavelength and the guided wavelength are given by 0.5 and 2 units respectively.
5.The basic formula for de Broglie wavelength is (A) = h/p = h/mv
E = kinetic energy = 1/2(mv^2) = eV
Here, e = electronic charge of the particle
Now, from the equation we get - mv = (2meV)^(1/2)
So, the wavelength, A = h/(2meV)^(1/2)
Here, h = 6.63 × 10^(−34) joule second
m = 9.1 × 10^(-31) kg
e = 1.6 × 10^(-19) coulombs
V = 10000 volt
Now, using the values we get , A = 1.226 × 10^(-11) meter = 0.1226 angstroms =122.6nm
6. If this is p the uncertainty in the momentum of electron, then the momentum of the electron should be at least of this order, that is p=1.05*10-20 kg m/sec. Therefore, if the electron exists in the nucleus, it should have an energy of the order of 19.6 MeV