- AHigh retentivity and low coercivity.
- BLow retentivity and low coercivity.
- CHigh retentivity and high coercivity.
- DLow retentivity and high coercivity.
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At a place the value of horizontal component of the earth's magnetic field H is 3
. A metallic rod AB of length 2 m placed in east-west direction, having the end A towards east, falls vertically downward with a constant velocity of 50 m/s. Which end of the rod becomes positively charged and what is the value of induced potential difference between the two ends
|
(a) End A, 3 |
(b) End A, 3 mV |
|
(c) End B, 3 |
(d) End B, 3 mV |
A capacitor having capacitance C is charged to a voltage V. It is then removed and connected in parallel with another identical capacitor which is uncharged. The new charge on each capacitor is now
|
(a) CV |
(b) CV / 2 |
(c) 2 CV |
(d) CV / 4 |
A network of four capacitors of capacity equal to
and
are conducted in a battery as shown in the figure. The ratio of the charges on
and
is

|
(a) |
(b) |
(c) |
(d) |
A sphere of radius 1 cm has potential of 8000 V, then energy density near its surface will be
|
(a) 64 |
(b) 8 |
(b) 8 |
(d) 2.83 |
In the given figure distance of the point from A where the electric field is zero is

|
(a) 20 cm |
(b) 10 cm |
(c) 33 cm |
(d) None of these |
The refractive index of water with respect to air is 4 / 3 and the refractive index of glass with respect to air is 3/2. The refractive index of water with respect to glass is
|
(a) |
(b) |
(c) |
(d) 2 |
Best neutron moderator is
|
(a) Berillium oxide |
(b) Pure water |
(c) Heavy water |
(d) Graphite |
Two charged spheres of radii 10 cm and 15 cm are connected by a thin wire. No current will flow, if they have
|
(a) The same charge on each |
(b) The same potential |
|
(c) The same energy |
(d) The same field on their surfaces |
If rotational velocity of a dynamo armature is doubled, then induced e.m.f. will become
|
(a) Half |
(b) Two times |
(c) Four times |
(d) Unchanged |