MCQ
Condition for destructive interference is__________ where $n=0,1,2,3, \ldots$
- Aphase difference $=2 n \pi$
- Bphase difference $=(2 n-1) \pi$
- Cphase difference $=(2 n+1) \pi$
- Dphase difference $=(2 n+1) \frac{\pi}{2}$
✓
Answer
C. phase difference $(2 n +1)$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
The impedance of a series L - C - R circuit in an AC circuit is.
In the Young’s double slit experiment, for which colour the fringe width is least
|
(a) Red |
(b) Green |
(c) Blue |
(d) Yellow |
A photon of energy hv is absorbed by o free electron of a metal having work function $\varphi<\text{hv}.$
→- The electron is sure to come out.
- The electron is sure to come out with a kinetic energy $\text{hv}-\varphi.$
- Either the electron does not come out or it comes out with a kinetic energy $\text{hv}-\varphi$ .
- It may come out with a kinetic energy less than $\text{hv}-\varphi.$
When a point source of light is at a distance of one metre from a photo cell, the cut off voltage is found to be V. If the same source is placed at 2 m distance from photo cell, the cut off voltage will be
|
(a) V |
(b) V/2 |
(c) V/4 |
(d) V/ |
Consider the following statements and select the correct option:
- In an external electric field, the positive and negative charges of a non–polar molecule are displaced in opposite directions.
- In non –polar molecules displacement stops when the external force on the constituent charges of the molecule is balanced by the restoring force.
- The non–polar molecule develops an induced dipole moment.
The half life of a radioactive element which has only 
of its original mass left after a lapse of 60 days is
|
(a) 12 days |
(b) 32 days |
(c) 60 days |
(d) 64 days |
Value of refractive index for any medium is:
An electron makes a transition from orbit n = 4 to the orbit n = 2 of a hydrogen atom. The wave number of the emitted radiations (R = Rydberg's constant) will be
|
(a) |
(b) |
(c) |
(d) |
If the refractive indices of a prism for red, yellow and violet colours be 1.61, 1.63 and 1.65 respectively, then the dispersive power of the prism will be
|
(a) |
(b) |
(c) |
(d) |
Two identical magnetic dipoles of magnetic moments 1.0 A-m2 each, placed at a separation of 2m with their axis perpendicular to each other. The resultant magnetic field at a point midway between the dipoles is
(a) 5 
|
(b) 
|
(c)
|
(d) None of these |