MCQ
Two uncharged bodies on rubbing, get charged due to:
- AConduction
- BFriction
- CInduction
- DNone of these
Explanation:
When two bodies are rubbed together, there is transfer of electrons because of friction.
Hence, two uncharged bodies on rubbing, gets equal and opposite charges.
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A bright star is indicated to have a brightness magnitude of – 5 compared to a star of brightness zero magnitude. It means that this star compared to the reference star of zero brightness is
|
(a) 100 times less bright |
(b) 5 times more bright |
|
(c) 5 times less bright |
(d) 100 times more bright |
A galvanometer of 25 W resistance can read a maximum current of 6mA. It can be used as a voltmeter to measure a maximum of 6 V by connecting a resistance to the galvanometer. Identify the correct choice in the given answers
|
(a) 1025 W in series |
(b) 1025 W in parallel |
(c) 975 W in series |
(d) 975 W in parallel |
The direction of induced e.m.f. during electromagnetic induction is given by
|
(a) Faraday's law |
(b) Lenz's law |
(c) Maxwell's law |
(d) Ampere's law |
In intrinsic semiconductor at room temperature, number of electrons and holes are
|
(a) Equal |
(b) Zero |
(c) Unequal |
(d) Infinite |
The relation among u, v and f for a mirror is:
The wavelength of de-Broglie wave is 2mm, then its momentum is (h = 6.63 × 10–34 J-s)
|
(a) 3.315 × 10–28 kg-m/s |
(b) 1.66 × 10–28 kg-m/s |
(c) 4.97 × 10–28 kg-m/s |
(d) 9.9 × 10–28 kg-m/s |