- Adirection
- Bmagnitude
- Cmagnitude and direction both
- Dnone
Explanation:
An alternating current (AC) is an electric current whose magnitude and direction vary, unlike direct current, whose direction remains constant.
The usual waveform of an AC power circuit is a sine wave, because this leads to the most efficient transmission of energy. The sine wave oscillates periodically between positive and negative direction.
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In a sample of radioactive material, what fraction of the initial number of active nuclei will remain undisintegrated after half of a half-life of the sample
|
(a) |
(b) |
(c) |
(d) 2 |
The potential at a distance R/2 from the centre of a conducting sphere of radius R will be
|
(a) 0 |
(b) |
(c) |
(d) |
α - particles of energy 400 KeV are bombarded on nucleus of
. In scattering of α - particles, its minimum distance from nucleus will be
|
(a) 0.59 nm |
(b) 0.59 Å |
(c) 5.9 pm |
(d) 0.59 pm |
In the lowest energy level of hydrogen atom, the electron has the angular momentum
|
(a) |
(b) h/ |
(c) h/2 |
(d) |
Which arrangement of four identical resistances should be used to draw maximum energy from a cell of voltage V
|
(a)
|
(b)
|
|
(c)
|
(d)
|
Assertion : Electric conduction in gases is possible at normal pressure.
Reason : The electric conduction in gases depends only upon the potential difference between the electrodes.
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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. |
Compton effect shows that
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(a) X-rays are waves |
(b) X-rays have high energy |
|
(c) X-rays can penetrate matter |
(d) Photons have momentum |
Following is the relation between current and charge
then value of VL will be
|
(a) |
(b) |
(c) |
(d) |