Explanation:
$\text{impedance}×\cos\theta = \text{resistance}$
$\text{impedance} = \frac{\text{resistance}}{\cos\theta}$
$=\frac{\sqrt{300}}{\frac{\cos\pi}{6}}$
$20\Omega$
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A conducting rod of length 2l is rotating with constant angular speed w about its perpendicular bisector. A uniform magnetic field 
exists parallel to the axis of rotation. The e.m.f. induced between two ends of the rod is
|
(a) Bω |
(b) |
(c) |
(d) Zero |
Consider the following two statements A and B and identify the correct choice in the given answer
A : The characteristic X-ray spectrum depends on the nature of the material of the target.
B : The short wavelength limit of continuous X-ray spectrum varies inversely with the potential difference applied to the X-rays tube
|
(a) A is true and B is false |
(b) A is false and B is true |
|
(c) Both A and B are true |
(d) Both A and B are false |
What kV potential is to be applied on X-ray tube so that minimum wavelength of emitted X-rays may be 1Å (h = 6.625 
J-sec)
|
(a) 12.42 kV |
(b) 12.84 kV |
(c) 11.98 kV |
(d) 10.78 kV |
A straight wire of diameter 0.5 mm carrying a current of 1 A is replaced by another wire of 1 mm diameter carrying the same current. The strength of magnetic field far away is
|
(a) Twice the earlier value |
(b) Half of the earlier value |
|
(c) Quarter of its earlier value |
(d) Unchanged |
