Light waves producing interference have their amplitudes in the ratio 3 : 2. The intensity ratio of maximum and minimum of interference fringes is
|
(a) 36 : 1 |
(b) 9 : 4 |
(c) 25 : 1 |
(d) 6 : 4 |
(c) 25 : 1
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The heating coils rating at 220 volt and producing 50 cal/sec heat are available with the resistances 55Ω,110 Ω, 220 Ω and 440 Ω. The heater of maximum power will be of
|
(a) 440 Ω |
(b) 220 Ω |
(c) 110 Ω |
(d) 55 Ω |
Self induction of a solenoid is
|
(a) Directly proportional to current flowing through the coil |
|
(b) Directly proportional to its length |
|
(c) Directly proportional to area of cross-section |
|
(d) Inversely proportional to area of cross-section |
The electric field E, current density J and conductivity s of a conductor are related as
|
(a) σ = E/j |
(b) σ = j/E |
(c) σ = jE |
(d) σ = 1/jE |
A nucleus is bombarded with a high speed neutron so that resulting nucleus is a radioactive one. This phenomenon is called
| (a) Artificial radioactivity | (b) Fusion | (c) Fission | (d) Radioactivity |
The condensers of capacity 
and 
are connected in parallel, then the equivalent capacitance is
|
(a) |
(b) |
(c) |
(d) |
The energy band gap is maximum in
|
(a) Metals |
(b) Superconductors |
(c) Insulators |
(d) Semiconductors |
Two charge + q and -q are situated at a certain distance. At the point exactly midway between them
|
(a) Electric field and potential both are zero |
|
(b) Electric field is zero but potential is not zero |
|
(c) Electric field is not zero but potential is zero |
|
(d) Neither electric field nor potential is zero |
The resistance of a conductor increases with
|
(a) Increase in length |
(b) Increase in temperature |
|
(c) Decrease in cross–sectional area |
(d) All of these |
