An iron cored coil is connected in series with an electric bulb with an AC source as shown in the figure. When iron piece is taken out of the coil, the brightness of the bulb will

If the rating of the voltmeter ${\mathrm{V}}_1$ is $40 \mathrm{V}$, then the reading of the voltmeter ${\mathrm{V}}_2$ is

The electric potential $\mathrm{V}$ as a function of distance $\mathrm{X}$ is shown in the figure.

The graph of the magnitude of electric field intensity $\mathrm{E}$ as a function of $\mathrm{X}$ is