- AHertz.
- BHallwachs.
- CLenard.
- DMillikan.
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Assertion : An ac generator is based on the phenomenon of self-induction.
Reason : In single coil, we consider self-induction only.
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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 assertion is false but reason is true. |
If the de-Broglie wavelengths for a proton and for a α - particle are equal, then the ratio of their velocities will be
|
(a) 4 : 1 |
(b) 2 : 1 |
(c) 1 : 2 |
(d) 1 : 4 |
A current of 2.0 ampere passes through a cell of e.m.f. 1.5 volts having internal resistance of 0.15 ohm. The potential difference measured, in volts, across both the ends of the cell will be
|
(a) 1.35 |
(b) 1.50 |
(c) 1.00 |
(d) 1.20 |
A combination of two thin lenses with focal lengths
and
respectively forms an image of distant object at distance 60 cm when lenses are in contact. The position of this image shifts by 30 cm towards the combination when two lenses are separated by 10 cm. The corresponding values of
and
are
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(a) 30 cm,-60 cm |
(b) 20 cm, -30 cm |
(c) 15 cm, -20 cm |
(d) 12 cm, - 15 cm |
A concave mirror gives an image three times as large as the object placed at a distance of 20 cm from it. For the image to be real, the focal length should be
|
(a) 10 cm |
(b) 15 cm |
(c) 20 cm |
(d) 30 cm |
As the intensity of incident light increases
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(a) Photoelectric current increases |
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(b) Photoelectric current decreases |
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(c) Kinetic energy of emitted photoelectrons increases |
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(d) Kinetic energy of emitted photoelectrons decreases |
If the ionisation potential of helium atom is 24.6 volt, the energy required to ionise it will be
|
(a) 24.6 eV |
(b) 24.6 V |
(c) 13.6 V |
(d) 13.6 eV |