Ray optics is valid, when characteristic dimensions are
|
(a) Of the same order as the wavelength of light |
|
(b) Much smaller than the wavelength of light |
|
(c) Of the order of one millimetre |
|
(d) Much larger than the wavelength of light |
(d) Much larger than the wavelength of light
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In the circuit shown in figure, the current drawn from the battery is 4A. If 10 W resistor is replaced by 20 W resistor, then current drawn from the circuit will be
|
(a) 1 A |
(b) 2 A |
(c) 3 A |
(d) 0 A |
A condenser has a capacity 2μF and is charged to a voltage of 50 V. The energy stored is
|
(a) 25 × 105 Joule |
(b) 25 Joule |
(c) 25 × 10 erg |
(d) 25 × 103 erg |
The magnetic induction in the region between the pole faces of an electromagnet is 0.7 weber/m2. The induced e.m.f. in a straight conductor 10 cm long, perpendicular to B and moving perpendicular both to magnetic induction and its own length with a velocity 2 m/sec is
|
(a) 0.08 V |
(b) 0.14 V |
(c) 0.35 V |
(d) 0.07 V |
A parallel plate capacitor of capacity 
is charged to a potential 
(i) The energy stored in the capacitor when the battery is disconnected and the separation is doubled 
(ii) The energy stored in the capacitor when the charging battery is kept connected and the separation between the capacitor plates is doubled is 
Then 
value is
|
(a) 4 |
(b) 3/2 |
(c) 2 |
(d) 1/2 |
Thirteen resistances each of resistance R ohm are connected in the circuit as shown in the figure below. The effective resistance between A and B is
|
(a) 2R W |
(b) |
(c) |
(d) R W |
A hole in a P-type semiconductor is
| (a) An excess electron | (b) A missing electron |
|
(c) A missing atom |
(d) A donor level |
