MCQ
The resistance of ideal ammeter is :
- ✓Zero
- BVery small
- CVery large
- DInfinite
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Laser beams are used to measure long distance because
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(a) They are monochromatic |
(b) They are highly polarised |
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(c) They are coherent |
(d) They have high degree of parallelism |
The maximum peak to peak voltage of an AM wire is 24 mV and the minimum peak to peak voltage is 8 mV. The modulation factor is
|
(a) 10% |
(b) 20% |
(c) 25% |
(d) 50% |
Two ends of a conductor are at different temperatures the electromotive force generated between two ends is
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(a) Seebeck electro motive force (e.m.f.) |
(b) Peltier electro motive force (e.m.f.) |
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(c) Thomson electro motive force (e.m.f.) |
(d) None of these |
Assertion : Microwave communication is preferred over optical communication.
Reason : Microwaves provide large number of channels and band width compared to optical signals.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
A conducting ring of radius 1 meter is placed in an uniform magnetic field B of 0.01Telsa oscillating with frequency 100Hz with its plane at right angles to B. What will be the induced electric field
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(a) π volt/m |
(b) 2 volt/m |
(c) 10 volt/m |
(d) 62 volt/m |
In case of NPN-transistors the collector current is always less than the emitter current because
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(a) Collector side is reverse biased and emitter side is forward biased |
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(b) After electrons are lost in the base and only remaining ones reach the collector |
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(c) Collector side is forward biased and emitter side is reverse biased |
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(d) Collector being reverse biased attracts less electrons |
The vertical component of earth's magnetic field is zero at or The earth's magnetic field always has a vertical component except at the
| (a) Magnetic poles | (b) Geographical poles | (c) Every place | (d) Magnetic equator |
When objects at different distances are seen by the eye, which of the following remain constant?