Question
Light enters an isosceles right triangular prism at normal incidence through face $A B$ and undergoes total internal reflection at face $B C$ as shown below.The minimum value of the refractive index of the prism is close to
✓
Answer
(c)
As total internal reflection occurs at angle of incidence, $i=45^{\circ}$.'
So, using $\mu=\frac{1}{\sin C}$, we have
$\mu=\frac{1}{\sin 45^{\circ}}=\sqrt{2} \text { or } \mu \approx 1.42$
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
Radioactive nuclei $P$ and $Q$ disintegrate into $R$ with half lives 1 month and 2 months respectively. At time $t=$ 0 , number of nuclei of each $P$ and $Q$ is $x$. Time at which rate of disintegration of $P$ and $Q$ are equal, number of nuclei of $R$ is ........ $x$
→Magnetostatic screening or shielding can be created by
A stone projected with a velocity u at an angle $\theta$ with the horizontal reaches maximum height $H_1$. When it is projected with velocity u at an angle $\left( {\frac{\pi }{2} - \theta } \right)$ with the horizontal, it reaches maximum height $ H_2$. The relation between the horizontal range R of the projectile, $H_1$ and $H_2$ is
→A block $'A'$ of mass $M$ moving with speed $u$ collides elastically with block $B$ of mass $m$ which is connected to block $C$ of mass $m$ with a spring. When the compression in spring is maximum the velocity of block $C$ with respect to block $A$ is (neglect friction)
→A block is being pulled by a force $F$ on a long frictionless level floor. Magnitude of the force is gradually increased from zero until the block lifts off the floor.Immediately after the block leaves the floor, its acceleration is
→A plane electromagnetic wave with frequency of $30 {MHz}$ travels in free space. At particular point in space and time, electric field is $6 {V} / {m}$. The magnetic field at this point will be ${x} \times 10^{-8} {T}$. The value of ${x}$ is ..... .
→$10\,Cells$, each of emf $'E'$ and internal resistance $'r'$, are connected in series to a variable external resistance. Figure shows the variation of terminal potential difference of their combination with the current drawn from the combination.$Emf$ of each cell is ............. $V$
→A particle moves in $xy$ plane according to the law $x = a \sin \omega t$ and $y = a(1-\cos \omega t)$ where $a$ and $\omega$ are constants. The particle traces
→One mole of an ideal gas is contained with in a cylinder by a frictionless piston and is initially at temperature $T$. The pressure of the gas is kept constant while it is heated and its volume doubles. If $R$ is molar gas constant, the work done by the gas in increasing its volume is
→$Assertion$ : There are very small sporadic changes in the speed of rotation of the earth
$Reason$ : Shifting of large air masses in the earth's atmosphere produce a change in the moment of inertia of the earth causing its speed of rotation to change.
→$Reason$ : Shifting of large air masses in the earth's atmosphere produce a change in the moment of inertia of the earth causing its speed of rotation to change.