Question

A bulb is rated (100 W, 110 V). It is operated by current of 1.0 A supplied by a step down transformer. If the input voltage and efficiency of the transformer are 220 V and 0.9 respectively, the input current drawn from the mains is :

Assertion (A) : The current density (J) at a point in a conducting wire is in the direction of electric field (E) at that point. Reason (R) : A conducting wire obeys Ohm's law.

Assertion (A) : The equivalent resistance between points A and B in the given network is 2R. Reason (R) : All the resistors are connected in parallel.

A battery is connected first across the series combination and then across the parallel combination, of three resistances R, 2R and 3R. In which of the three resistances will power dissipated be maximum in the two cases ? Justify your answer.