Threshold wavelength for photoelectric effect on sodium is 5000 Å. Its work function is
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(a) 15 J |
(b) 16 |
(c) 4 |
(d) 4 |
Threshold wavelength for photoelectric effect on sodium is 5000 Å. Its work function is
|
(a) 15 J |
(b) 16 |
(c) 4 |
(d) 4 |
(c) 4
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In a diode valve, the state of saturation can be obtained easily by
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(a) High plate voltage and high filament current |
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(b) Low filament current and high plate voltage |
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(c) Low plate voltage and high cathode temperature |
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(d) High filament current and high plate voltage |
Two charges each of 1 coulomb are at a distance 1 km apart, the force between them is
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(a) |
(b) 9 |
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(c) |
(d) |
Sodium and copper have work functions 2.3eV and 4.5eV respectively. Then the ratio of their threshold wavelengths is nearest to
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(a) 1: 2 |
(b) 4 : 1 |
(c) 2 : 1 |
(d) 1 : 4 |
When light is incident on a doubly refracting crystal, two refracted rays-ordinary ray (O-ray) and extra ordinary ray (E-ray) are produced. Then
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(a) Both O-ray and E-ray are polarised perpendicular to the plane of incidence |
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(b) Both O-ray and E-ray are polarised in the plane of incidence |
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(c) E-ray is polarised perpendicular to the plane of incidence and O-ray in the plane of incidence |
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(d) E-ray is polarised in the plane of incidence and O-ray perpendicular to the plane of incidence |
Particle nature and wave nature of electromagnetic waves and electrons can be shown by
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(a) Electron has small mass, deflected by the metal sheet |
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(b) X-ray is diffracted, reflected by thick metal sheet |
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(c) Light is refracted and defracted |
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(d) Photoelectricity and electron microscopy |
If the amplitude ratio of two sources producing interference is 3 : 5, the ratio of intensities at maxima and minima is
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(a) 25 : 16 |
(b) 5 : 3 |
(c) 16 : 1 |
(d) 25 : 9 |
Holes are charge carriers in
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(a) Intrinsic semiconductors |
(b) P-type semiconductors |
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(c) Metals |
(d) a, b |
Assertion : NAND or NOR gates are called digital building blocks.
Reason : The repeated use of NAND (or NOR) gates can produce all the basic or complicated gates.
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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. |
Quantity that remains unchanged in a transformer is
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(a) Voltage |
(b) Current |
(c) Frequency |
(d) None of the above |