- A$3~\mu F,$ $12~\mu F$
- B$2~\mu F,$ $12~\mu F$
- ✓$2~\mu F,$ $18~\mu F$
- D$6~\mu F,$ $18~\mu F$
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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
|
(a) 4 A |
(b) 0.4 A |
(c) 0.04 A |
(d) 0.2 A |
A ring of radius R, made of an insulating material carries a charge Q uniformly distributed on it. If the ring rotates about the axis passing through its centre and normal to plane of the ring with constant angular speed ω, then the magnitude of the magnetic moment of the ring is
|
(a) Qω |
(b) |
(c) Q |
(d) |
A radioactive reaction is
→
. How many α and β particles are emitted
|
(a) 10α, 6β |
(b) 4 protons, 8 neutrons |
|
(c) 6 electrons, 8 protons |
(d) 6β, 8α |
Critical angle of light passing from glass to air is minimum for
|
(a) Red |
(b) Green |
(c) Yellow |
(d) Violet |
Two circuits have coefficient of mutual induction of 0.09 henry. Average e.m.f. induced in the secondary by a change of current from 0 to 20 ampere in 0.006 second in the primary will be
|
(a) 120 V |
(b) 80 V |
(c) 200 V |
(d) 300 V |
The resistance of 1 A ammeter is 0.018 Ω . To convert it into 10 A ammeter, the shunt resistance required will be
|
(a) 0.18 Ω |
(b) 0.0018 Ω |
(c) 0.002 Ω |
(d) 0.12 Ω |