A filament bulb $\left(500 \mathrm{W}, 100 \mathrm{V}\right)$ is to be used in a $230 \mathrm{V}$ main supply. When a resistance, $R$ is connected in series, it works perfectly and the bulb consumes, $500 \mathrm{W}$. The value of, $R$ is

A carbon resistance has a following colour code. What is the value of the resistance ?

A battery has an $\mathrm{e}\mathrm{m}\mathrm{f}$ of $15\mathrm{ }\mathrm{V}$ and internal resistance of $1 \mathrm{\Omega }$ . The terminal to terminal potential difference is less than, equal to or greater than $15\mathrm{ }\mathrm{V}$, if the current in the battery is

(1) from negative to positive terminal,

(2) from positive to negative terminal,

(3) zero current?