Statement I: If bob of a simple pendulum is kept in a horizontal electric field, its period of oscillation will remain same.
Statement II: If bob is charged and kept in horizontal electric field, then the time period will be decreased.

When an uncharged bob of a pendulum is placed in an electric field, it does not affect its time period as no electric force can be experienced by the bob  since it is neutral. So, the acceleration of the bob remains same, i.e., g and hence its time period. But when a charged bob of a pendulum is placed in horizontal electric field, the bob experiences an electric force in horizontal direction due to which the effective value of g increases. Hence, its time period decreases.