The emf of a cell of internal resistance $2 \Omega$ is measured using a voltmeter of resistance $998 \Omega$. The error in the emf measured is

In a meter bridge experiment, a resistance of $9 \Omega$ is connected in the left gap and an unknown resistance greater than $9 \Omega$ is connected in right gap. If the resistance in the gaps are interchanged, the balancing point shifts by 10 cm . The unknown resistance is

A charge $q$ is spread uniformly over an isolated ring $R$. The ring is rotated about its natural axis with angular speed $\omega$. The magnetic dipole moment of the ring is

Current sensitivities of two galvanometers $G_1$ and $G_2$ of resistances $100 \Omega$ and $50 \Omega$ are $10^8 \mathrm{div} / \mathrm{A}$ and $0.5 \times 10^5 \mathrm{div} / \mathrm{A}$ respectively. The galvanometer in which the voltage sensitivity is more is $100 \Omega$