A wire of uniform cross section and resistance 4 ohms is bent in the shape of square ABCD. Point A is connected to a point $$\mathrm{P}$$ on DC by a wire AP of resistance $$1 \mathrm{ohm}$$. When a potential difference is applied between $$\mathrm{A}$$ and $$\mathrm{C}$$, the points $$\mathrm{B}$$ and $$\mathrm{P}$$ are seen to be in same potential. What is the resistance of part $$\mathrm{DP}$$ ?

A storage battery of emf $$28.0 \mathrm{~V}$$ and internal resistance $$0.5 \Omega$$ is being charged by a $$140 \mathrm{~V}$$ dc supply using a series resistor of $$27.5 \Omega$$. The terminal voltage of the battery during charging is

The resistance of the galvanometer and shunt of an ammeter are $$90 \mathrm{~ohm}$$ and $$10 \mathrm{~ohm}$$ respectively, then the fraction of the main current passing through the galvanometer and the shut respectively are:

A $$500 \mathrm{~W}$$ heating unit is designed to operate on a $$400 \mathrm{~V}$$ line. If line voltage drops to $$160 \mathrm{~V}$$, the percentage drop in heat output will be: