ABC is an equilateral triangle. Charges + q are placed at each corner. The electric intensity at O will be
|
(a) |
(b) |
(c) Zero |
(d) |
ABC is an equilateral triangle. Charges + q are placed at each corner. The electric intensity at O will be
|
(a) |
(b) |
(c) Zero |
(d) |
(c) Zero
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Which of the following statements concerning the depletion zone of an unbiased PN junction is (are) true
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(a) The width of the zone is independent of the densities of the dopants (impurities) |
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(b) The width of the zone is dependent on the densities of the dopants |
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(c) The electric field in the zone is produced by the ionized dopant atoms |
|
(d) b, c |
The ionisation potential of H-atom is 13.6 V. When it is excited from ground state by monochromatic radiations of 970.6
the number of emission lines will be (according to Bohr’s theory)
|
(a) 10 |
(b) 8 |
(c) 6 |
(d) 4 |
A light has amplitude A and angle between analyser and polariser is 60°. Light is reflected by analyser has amplitude
|
(a) A |
(b) A/ |
(c) |
(d) A/2 |
Assertion : The lightening conductor at the top of high building has sharp pointed ends.
Reason : The surface density of charge at sharp points is very high resulting in setting up of electric wind.
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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. |
The current sensitivity of a moving coil galvanometer can be increased by
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(a) Increasing the magnetic field of the permanent magnet |
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(b) Increasing the area of the deflecting coil |
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(c) Increasing the number of turns in the coil |
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(d) a, b, c |

Every series of hydrogen spectrum has an upper and lower limit in wavelength. The spectral series which has an upper limit of wavelength equal to 18752 Å is (Rydberg constant
per metre)
|
(a) Balmer series |
(b) Lyman series |
(c) Paschen series |
(d) Pfund series |