P-type semiconductor is formed when
A. As impurity is mixed in Si B. Al impurity is mixed in Si
C. B impurity is mixed in Ge D. P impurity is mixed in Ge
|
(a) A and C |
(b) A and D |
(c) B and C |
(d) B and D |
(c) B and C
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In a common emitter transistor, the current gain is 80. What is the change in collector current, when the change in base current is 250 mA
|
(a) 80 × 250 mA |
(b) (250 – 80) mA |
(c) (250 + 80) mA |
(d) 250/80 mA |
In a YDSE bi-chromatic light of wavelengths 400 nm and 560 nm are used. The distance between the slits is 0.1 mm and the distance between the plane of the slits and the screen is 1m. The minimum distance between two successive regions of complete darkness is
|
(a) 4 mm |
(b) 5.6 mm |
(c) 14 mm |
(d) 28 mm |
Two thin lenses of focal lengths f1 and f2 are in contact. The focal length of this combination is
|
(a) |
(b) |
(c) |
(d) |
Due to the flow of current in a circular loop of radius R, the magnetic induction produced at the centre of the loop is B. The magnetic moment of the loop is (
|
(a) |
(b) |
(c) |
(d) |
Two capacitors of 1mF and 2mF are connected in series, the resultant capacitance will be
|
(a) 4μF |
(b) |
(c) |
(d) 3 μF |
The Bohr radius of the fifth electron of phosphorus (atomic number = 15) acting as dopant in silicon (relative dielectric constant = 12) is
|
(a) 10.6 Å |
(b) 0.53 Å |
(c) 21.2 Å |
(d) None of these |
A current of 16 ampere flows through molten NaCl for 10 minute. The amount of metallic sodium that appears at the negative electrode would be
|
(a) 0.23 gm |
(b) 1.15 gm |
(c) 2.3 gm |
(d) 11.5 gm |
