The thermodynamic process in which no work is done on or by the gas is

The given circuit has two ideal diodes $$D_1$$ and $$D_2$$ connected as shown in the figure. The current flowing through the resistance $$R_1$$ will be

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)