An achromatic prism is made by combining two prisms 
and
; where μ represents the refractive index. If the angle of the prism 
is 10°, then the angle of the prism P2 will be
|
(a) 5° |
(b) 7.8° |
(c) 10.6° |
(d) 20° |
(a) 5°
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There is a current of 20 amperes in a copper wire of 
square metre area of cross-section. If the number of free electrons per cubic metre is 
, then the drift velocity is
|
(a) 125 |
(b) 12.5 |
(c) 1.25 |
(d) 1.25 |
Line spectrum contains information about
|
(a) The atoms of the prism |
|
(b) The atoms of the source |
|
(c) The molecules of the source |
|
(d) The atoms as well as molecules of the source |
In the experiment of diffraction at a single slit, if the slit width is decreased, the width of the central maximum
|
(a) Increases in both Fresnel and Fraunhofer diffraction |
|
(b) Decreases both in Fresnal and Fraunhofer diffraction |
|
(c) Increases in Fresnel diffraction but decreases in Fraunhofer diffraction |
|
(d) Decreases in Fresnel diffraction but increases is Fraunofer diffraction. |
For a given temperature difference, which of the following pairs will generate maximum thermo e.m.f.
|
(a) Antimony-bismuth |
(b) Silver-gold |
(c) Iron-copper |
(d) Lead-nickel |
Electric room radiator which operates at 225 volts has resistance of 50 ohms. Power of the radiator is approximately
|
(a) 100 W |
(b) 450 W |
(c) 750 W |
(d) 1000 W |
Assertion : The cloud in sky generally appear to be whitish.
Reason : Diffraction due to clouds is efficient in equal measure at all wavelengths.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
