In a Fraunhofer diffraction at a single slit of width 'd' and incident light of wavelength $$5500 \mathop A\limits^o$$, the first minimum is observed at an angle $$30^{\circ}$$. The first secondary maxima is observed at an angle $$\theta$$, equal to
A galvanometer of resistance $$200 \Omega$$ is to be converted into an ammeter. The value of shunt resistance which allows $$3 \%$$ of the mains current through the galvanometer is equal to (nearly)
The speed of light in two media $$M_1$$ and $$M_2$$ are $$1.5 \times 10^8$$ $$\mathrm{m} / \mathrm{s}$$ and $$2 \times 10^8 \mathrm{~m} / \mathrm{s}$$ respectively. If the light undergoes total internal reflection, the critical angle between the two media is
The minimum distance between an object and its real image formed by a convex lens of focal length 'f' is