- 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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The heat generated through 2 ohm and 8 ohm resistances separately, when a condenser of 200 μF capacity charged to 200 V is discharged one by one, will be
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(a) 4 J and 16 J respectively |
(b) 16 J and 4 J respectively |
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(c) 4 J and 8 J respectively |
(d) 4 J and 4 J respectively |
In semiconductors at a room temperature
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(a) The valence band is partially empty and the conduction band is partially filled |
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(b) The valence band is completely filled and the conduction band is partially filled |
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(c) The valence band is completely filled |
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(d) The conduction band is completely empty |
A power transformer is used to step up an alternating e.m.f. of 220 V to 11 kV to transmit 4.4 kW of power. If the primary coil has 1000 turns, what is the current rating of the secondary ? Assume 100% efficiency for the transformer
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(a) 4 A |
(b) 0.4 A |
(c) 0.04 A |
(d) 0.2 A |

A plane mirror is approaching you at a speed of 10 cm/sec You can see your image in it. At what speed will your image approach you
| (a) 10 cm/sec | (b) 5 cm/sec | (c) 20 cm/sec | (d) 15 cm/sec |