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Work done W = F x d Only when there is distance moved in the direction of the force , there is work done. (i.e. look for the distance parallel to the force)

Solutions: Option B As lamp X is thicker and shorter , these two factors make the resistance of X lower than Y . Recall: Length increases, R increases & cross-sectional area increases, R decreases. [R = pL/A] As both bulbs are connected to the same mains, (assume 240V), the potential difference across the bulbs are 240 V. Brightness of the bulb depends on power , P = IV or V2/R, since V is constant, I across X is higher due to lower R,hence power of X is greater than power of Y, hence X is brighter .

Solutions: Option B Whatever that goes in has to come out. With this basic concept, you will be able to solve this question easily. Ignoring the unknown branch, Total current going into O = 8A + 6A = 14A Total current going out of O = 12A + 4A = 16A Hence in order to be equal, 2A must be flowing in direction PO. Hence answer is B.

Based on individual calculations, the highest effective resistance will only be achieved if the junctions are connected at Q and S.