MCQ
A very thin film in reflected white light appears:
- Acoloured
- Bwhite
- Cblack
- Dred
✓
Answer
- black
Explanation:
For very thin films the distance travelled inside the film is insignificant and so the two reflected waves are almost exactly out of phase with each other (due to the phase change at one surface); they interfere destructively and the film appears 'black'.
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
Identify the type of materials which have resistivities in the range of 10-8 Ωm to 10-6 Ωm.
Magnetic field intensity at the centre of coil of 50 turns, radius 0.5 m and carrying a current of 2 A is
|
(a) 0.5 |
(b) 1.25 |
(c) 3 |
(d) 4 |
In a P-type semiconductor
|
(a) Current is mainly carried by holes |
|
(b) Current is mainly carried by electrons |
|
(c) The material is always positively charged |
|
(d) Doping is done by pentavalent material |
Which of the following sources gives best monochromatic light?
In the given circuit, with steady current, the potential drop across the capacitor must be
|
(a) V |
(b) V / 2 |
(c) V / 3 |
(d) 2V / 3 |
Consider an extended object immersed in water contained in a plane trough. When seen from close to the edge of the trough the object looks distorted because:
If a comb is rubbed on dry hairs, and then brought near paper pieces, it:
Reciprocal of Impedance is:
The resistance of an ideal ammeter is
|
(a) Infinite |
(b) Very high |
(c) Small |
(d) Zero |
Which of the following isotopes is likely to be most stable?