- AAll points are in the same phase.
- BThere is a pair of points in opposite phase.
- CThere is a pair of points with phase difference $(\frac{\pi}{2})$.
- DThere is no relation between the phases.
Explanation:
A wavefront is the locus of points characterized by propagation of position of the same phase:
a propagation of a line in 1D, a curve in 2D or a surface for a wave in 3D.
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A particle of mass M and charge Q moving with velocity describes a circular path of radius R when subjected to a uniform transverse magnetic field of induction B. The work done by the field when the particle completes one full circle is
|
(a) BQv2πR |
(b) |
(c) Zero |
(d) BQ |
In the lowest energy level of hydrogen atom, the electron has the angular momentum
|
(a) |
(b) h/ |
(c) h/2 |
(d) |
In the circuit shown here, what is the value of the unknown resistor R so that the total resistance of the circuit between points P and Q is also equal to R

|
(a) 3 ohms |
(b) |
(c) |
(d) 10 ohms |
A wire when connected to 220V mains supply has power dissipation . Now the wire is cut into two equal pieces which are connected in parallel to the same supply. Power dissipation in this case is
. Then
is
|
(a) 1 |
(b) 4 |
(c) 2 |
(d) 3 |
A plane electromagnetic wave is incident on a material surface. If the wave delivers momentum p and energy E, then
| (a) p = 0, E = 0 | (b) p ¹ 0, E ¹ 0 | (c) p ¹ 0, E = 0 | (d) p = 0, E ¹ 0 |
Two rays A and B being reflected by a mirror and going as A' and B'. The mirror:

The energy of a hydrogen atom in its ground state is -13.6eV. The energy of the level corresponding to the quantum number n = 2 (first excited state) in the hydrogen atom is
|
(a) – 2.72 eV |
(b) – 0.85 eV |
(c) – 0.54 eV |
(d) – 3.4 eV |
Which of the following rays are not electromagnetic waves
|
(a) g-rays |
(b) b-rays |
(c) Heat rays |
(d) X-rays |