Two small charges +4.0 x 10-5 C and -1.8 x 10-5 C, are placed 24 cm apart. What is the force on the third small charge, of magnitude -2.5 x 10-6 C, if it is placed on the line joining the other two and (a) 12 cm to the outside of them, on the side of the negative one? (b) 12 cm to the outside of them, on the side of the positive one? (c) midway between them?

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