- AHigh retentivity and high coercive force.
- BHigh retentivity and low coercive force.
- CLow retentivity and high coercive force.
- DLow retentivity and low coercive force.
Explanation:
Permanent magnetis are High retentivity and High coercive force.
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A bi-convex lens made of glass (refractive index 1.5) is put in a liquid of refractive index 1.7. Its focal length will
|
(a) Decrease and change sign |
|
(b) Increase and change sign |
|
(c) Decrease and remain of the same sign |
|
(d) Increase and remain of the same sign |
A proton of mass m and charge +e is moving in a circular orbit in a magnetic field with energy 1 MeV. What should be the energy of α - particle (mass = 4m and charge = + 2e), so that it can revolve in the path of same radius
|
(a) 1 MeV |
(b) 4 MeV |
(c) 2 MeV |
(d) 0.5 MeV |
A crystal diode is a
|
(a) Non-linear device |
(b) Amplifying device |
(c) Linear device |
(d) Fluctuating device |
A beam of ions with velocity 2
enters normally into a uniform magnetic field of 4
If the specific charge of the ion is 5
, then the radius of the circular path described will be
|
(a) 0.10 m |
(b) 0.16 m |
(c) 0.20 m |
(d) 0.25 m |
At neutral temperature, the thermoelectric power
has the value
|
(a) Zero |
(b) Maximum but negative |
|
(c) Maximum but positive |
(d) Minimum but positive |
A ray of light of intensity I is incident on a parallel glass-slab at a point A as shown in fig. It undergoes partial reflection and refraction. At each reflection 25% of incident energy is reflected. The rays AB and A'B' undergo interference. The ratio is
|
(a) 4 : 1 |
(b) 8 : 1 |
(c) 7 : 1 |
(d) 49 : 1 |
What is the ratio of wavelength of radiations emitted when an electron in hydrogen atom jump from fourth orbit to second orbit and from third orbit to second orbit
| (a) 27 : 25 | (b) 20 : 27 |
(c) 20 : 25 |
(d) 25 : 27 |
