The rating of an electric lamp is 110 V. To use it to 220 V, one will have to use which one of the following?

To use a 110 V lamp on a 220 V supply, the excess voltage must be dropped across another component connected in series. According to Ohm's law and series circuit principles, a resistor can be used to create a potential difference, effectively reducing the voltage reaching the lamp [c3]. While a step-down transformer is a highly efficient and common method for converting 220 V to 110 V [t1][t3], the question asks what 'one' will have to use in a simple circuit context. In basic electrical problems of this nature, adding a series resistor is the standard method to limit current and drop voltage [c3][t2]. A transistor is typically used for regulation or switching [t2][t4], and a generator produces power rather than converting it. Therefore, a resistor is the most fundamental component used to drop the specific voltage required for the lamp to operate safely.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > Solution > p. 185