Explanation:
$\text{i}=\text{i}_1\cos\omega\text{t}+\text{i}_2\sin\omega\text{t}$
$\text{I}_\text{rms}=\frac{\int\limits_0^\text{T}\text{I}^2\text{dt}}{\int\limits_0^\text{T}\text{dt}}$
if $\text{I}=\cos\omega\text{t}$
$\text{I}_\text{rms}^2=\frac{\text{I}_0^2}{2}$
$\text{i}=\text{i}_1\cos\omega\text{t}+\text{i}_2\sin\omega\text{t}$
Than $\text{i}_\text{rms}^2=\frac{\text{i}_1^2}{2}+\frac{\text{i}_2^2}{2}$
$\text{i}_\text{rms}=\sqrt{\frac{\text{i}_1^2+\text{i}_2^2}{2}}$
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Assertion : The induced e.m.f. and current will be same in two identical loops of copper and aluminium, when rotated with same speed in the same magnetic field.
Reason : Induced e.m.f. is proportional to rate of change of magnetic field while induced current depends on resistance of wire.
|
(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 assertion is false but reason is true. |
A charge q is placed at the centre of the open end of cylindrical vessel. The flux of the electric field through the surface of the vessel is
|
(a) Zero |
(b) |
(c) |
(d) |
The earth's magnetic induction at a certain point is 7 × 
. This is to be annulled by the magnetic induction at the centre of a circular conducting loop of radius 5 cm. The required current in the loop is
|
(a) 0.56 A |
(b) 5.6 A |
(c) 0.28 A |
(d) 2.8 A |
CO2 gas is found in which of the following pairs of the planet
|
(a) Earth and Mercury |
(b) Mercury and Saturn |
|
(c) Venus and Saturn |
(d) Venus and Mars |
Donor type impurity is found in
|
(a) Trivalent elements |
(b) Pentavalent elements |
|
(c) In both the above |
(d) None of these |
In a full wave rectifiers, input ac current has a frequency ‘n’. The output frequency of current is
|
(a) n/2 |
(b) n |
(c) 2n |
(d) None of these |
The work function of metal is 1 eV. Light of wavelength 3000 Å is incident on this metal surface. The velocity of emitted photo-electrons will be
|
(a) 10 m/sec |
(b) 1 |
(c) |
(d) |
