In a wheatstone's bridge, three resistances $$\mathrm{P}, \mathrm{Q}$$ and $$\mathrm{R}$$ are connected in the three arms and the fourth arm is formed by two resistances $$S_1$$ and $$S_2$$ connected in parallel. The condition for the bridge to be balanced is

If a current flowing in a coil is reduced to half of its initial value, the relation between the new energy $$\left(E_2\right)$$ and the original energy $$\left(E_1\right)$$ stored in the coil will be

The critical angle for light going from medium A into medium B is $$\theta$$. The speed of light in the medium A is $$\mathrm{V}_{\mathrm{A}}$$. What is the speed of light in the medium $$\mathrm{B}$$ ?

Which of the following statements is true?

($$\Delta \mathrm{U}=$$ increase in internal energy, $$\mathrm{dW}=$$ work done by the system)