MCQ
The wavefront due to point source at a finite distance from the source is :
- ✓Spherical
- BCylindrical
- CPlane
- DCircular
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The condition for observing Fraunhofer diffraction from a single slit is that the light wavefront incident on the slit should be
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(a) Spherical |
(b) Cylindrical |
(c) Plane |
(d) Elliptical |
Radius of the first orbit of the electron in a hydrogen atom is 0.53 Å. So, the radius of the third orbit will be
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(a) 2.12 Å |
(b) 4.77 Å |
(c) 1.06 Å |
(d) 1.59 Å |
A change of 0.8 mA in the anode current of a triode occurs when the anode potential is changed by 10 V. If m = 8 for the triode, then what change in the grid voltage would be required to produce a change of 4 mA in the anode current
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(a) 6.25 V |
(b) 0.16 V |
(c) 15.2 V |
(d) None of these |
Assertion : In all conductors, for studying the thermoelectric behaviour or metals, lead is taken as a reference metal.
Reason : In lead, the Thomson effect is negative.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
In a step up transformer, if ratio of turns of primary to secondary is 1 : 10 and primary voltage is 230 V. If the load current is 2A, then the current in primary is
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(a) 20 A |
(b) 10 A |
(c) 2 A |
(d) 1 A |
If scattering particles are 56 for 90° angle then this will be at 60° angle
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(a) 224 |
(b) 256 |
(c) 98 |
(d) 108 |
Given a point source of light, which of the following can produce a parallel beam of light
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(a) Convex mirror |
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(b) Concave mirror |
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(c) Concave lens |
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(d) Two plane mirrors inclined at an angle of 90° |