Question
The phenomenon utilised in an optical fibre is
|
(a) Refraction |
(b) Interference |
|
(c) Polarization |
(d) Total internal reflection |
✓
Answer
(d) Total internal reflection
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
A ray of light passes through four transparent media with refractive indices 
and 
as shown in the figure. The surfaces of all media are parallel. If the emergent ray CD is parallel to the incident ray AB, we must have
|
(a) |
(b) |
(c) |
(d) |
Which of the following is the radio isotope in this pair?$39\text{K}\\19$,$40\text{K}\\19$
→The frequency of 1st line of Balmer series in 
atom is 
. The frequency of line emitted by singly ionised He atom is
|
(a) 2 |
(b) 4 |
(c) |
(d) |
Assertion : Interference pattern is made by using blue light instead of red light, the fringes becomes narrower.
Reason : In Young’s double slit experiment, fringe width is given by relation B = 
|
(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 the assertion and reason both are false. |
The frequency of light ray having the wavelength 3000 Å is
|
(a) 9 × 1013 cycles/sec |
(b) 1015 cycles/sec |
(c) 90 cycles/sec |
(d) 3000 cycles/sec |
A hydrogen like atom of atomic number Z is in an excited state of quantum number 2n. It can emit a maximum energy photon of 204 eV. If it makes a transition to quantum state n, a photon of energy 40.8 eV is emitted. The value of n will be
|
(a) 1 |
(b) 2 |
(c) 3 |
(d) 4 |
When a drop of oil is spread on a water surface, it displays beautiful colours in daylight because of:
- Disperson of light.
- Reflection of light.
- Polarization of light.
- Interference of light.
50% of the X-rays coming from a Coolidge tube are able to pass through a 0.1mm thick aluminium foil. If the potential difference between the target and the filament is increased, the fraction of the X-rays passing through the same foil will be:
Which of the following statement is incorrect
|
(a) Both ac and dc dynamo have a field magnet |
|
(b) Both ac and dc dynamo have an armature |
|
(c) Both ac and dc dynamo convert mechanical energy into electrical energy |
|
(d) Both ac and dc dynamo have slip rings |
S is the surface of a lump of magnetic material: