- 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 PN-junction diode
|
(a) The current in the reverse biased condition is generally very small |
|
(b) The current in the reverse biased condition is small but the forward biased current is independent of the bias voltage |
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(c) The reverse biased current is strongly dependent on the applied bias voltage |
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(d) The forward biased current is very small in comparison to reverse biased current |
Which of the following is quantised according to Bohr’s theory of hydrogen atom
| (a) Linear momentum of electron | (b) Angular momentum of electron |
| (c) Linear velocity of electron | (d) Angular velocity of electron |
$\frac{1}{\text{v}}-\frac{1}{\text{u}}=\frac{1}{\text{uf}}$
$\frac{1}{\text{v}^2}-\frac{1}{\text{u}}=\frac{1}{\text{f}}$
$\frac{1}{\text{v}-\text{t}}-\frac{1}{\text{u}+\text{t}}=\frac{1}{\text{f}}$
$\frac{1}{\text{v}}-\frac{1}{\text{u}}+\frac{\text{t}}{\text{uv}}=\frac{\text{t}}{\text{f}}$
Assertion : Isobars are the element having same mass number but different atomic number.
Reason : Neutrons and protons are present inside nucleus.
|
(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. |
|
(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
An electron and a proton with equal momentum enter perpendicularly into a uniform magnetic field, then
|
(a) The path of proton shall be more curved than that of electron |
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(b) The path of proton shall be less curved than that of electron |
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(c) Both are equally curved |
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(d) Path of both will be straight line |
If identical charges (-q) are placed at each corner of a cube of side b, then electric potential energy of charge (+q) which is placed at centre of the cube will be
|
(a) |
(b) |
(c) |
(d) |
Two radioactive materials
and
have decay constants 10λ and λ respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of
to that of
will be 1/e after a time
|
(a) 1/(10 λ) |
(b) 1/(11 λ) |
(c) 11(10 λ) |
(d) 1(9 λ) |
Assertion : Magnetism is relativistic.
Reason : When we move along with the charge so that there is no motion relative to us, we find no magnetic field associated with the charge.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |