Explanation:
electromagnetic radiation consists of electromagnetic waves, which are synchronized oscillations of electric and magnetic fields that propagate at the speed of light through a vaccum. The oscillations of the two fields are perpendicular to each other and perpendicular to the direction of energy and wave propagation, forming a transverse wave. so if propogation is along Y-direction ,Electric field will be along X or Z, if it is along Z -direction than Magnetic field has to be in X -direction.
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Radius of the first orbit of the electron in a hydrogen atom is 0.53 Å. So, the radius of the third orbit will be
|
(a) 2.12 Å |
(b) 4.77 Å |
(c) 1.06 Å |
(d) 1.59 Å |
$\text{I}_0$
$\frac{\text{I}_0}{4}$
$\frac{\text{I}_0}{2}$
$4\text{I}_0$
The third line of Balmer series of an ion equivalent to hydrogen atom has wavelength of 108.5 nm. The ground state energy of an electron of this ion will be
|
(a) 3.4 eV |
(b) 13.6 eV |
(c) 54.4 eV |
(d) 122.4 eV |
The half-life of a radioactive substance is 3.6 days. How much of 20 mg of this radioactive substance will remain after 36 days
|
(a) 0.0019 mg |
(b) 1.019 mg |
(c) 1.109 mg |
(d) 0.019 mg |
If a diamagnetic substance is brought near north or south pole of a bar magnet, it is
| (a) Attracted by the poles |
| (b) Repelled by the poles |
|
(c) Repelled by the north pole and attracted by the south pole |
|
(d) Attracted by the north pole and repelled by the south pole |
A molecule with a dipole moment p is placed in an electric field of strength E. Initially the dipole is aligned parallel to the field. If the dipole is to be rotated to be anti-parallel to the field, the work required to be done by an external agency is
|
(a) – 2pE |
(b) – pE |
(c) pE |
(d) 2pE |