Download App

Wave Optics — JEE physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceJEE physicsWave Optics1 Mark
Question
Assertion : The film which appears bright in reflected system will appear dark in the transmitted light and vice-versa.
Reason : The conditions for film to appear bright or dark in reflected light are just reverse to those in the transmitted light.
✓

Answer

(a) For reflected system of the film, the maxima or constructive interference is $2 \mu t \cos r=\frac{(2 n-1) \lambda}{2}$ while the maxima for transmitted system of film is given by equation $2 \mu t \cos r=n \lambda$where $t$ is thickness of the film and $r$ is angle of reflection.From these two equations we can see that condition for maxima in reflected system and transmitted system are just opposite.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Assertion & Reason" from Wave Optics→Wave Optics — all question types→JEE physics STD 12 Science question papers→CBSE Board STD 12 Science question papers→CBSE Board question paper generator→

Similar questions

Assertion : Silicon is preferred over germanium for making semiconductor devices.
Reason : The energy gap for germanium is more than the energy gap of silicon.
→
Assertion : The graph between velocity and displacement for a harmonic oscillator is a parabola.
Reason : Velocity does not change uniformly with displacement in harmonic motion.
→
Assertion : Density is a derived physical quantity.
Reason : Density cannot be derived from the fundamental physical quantities.
→
Assertion : Zener diode works on a principle of breakdown voltage.
Reason : Current increases suddenly after breakdown voltage.
→
Assertion : Water at the foot of the water fall is always at different temperature from that at the top.
Reason : The potential energy of water at the top is converted into heat energy during falling.
→
Assertion : The basic of Laplace correction was that, exchange of heat between the region of compression and rarefaction in air is not possible.
Reason : Air is a bad conductor of heat and velocity of sound in air is large.
→
Assertion : The position-time graph of a body moving uniformly is a straight line parallel to position-axis.
Reason : The slope of position-time graph in a uniform motion gives the velocity of an object.
→
Assertion : Television signals are received through sky-wave propagation.
Reason : The ionosphere reflects electromagnetic waves of frequencies greater than a certain critical frequency.
→
Assertion $\quad$ : Vector addition is commutative.
Reason $\quad: \quad(\vec{A}+\vec{B}) \neq(\vec{B}+\vec{A})$.
→
Assertion : The flash of lightening is seen before the sound of thunder is heard.
Reason $\quad$ Speed of sound is greater than speed of light
→