The electric dipole moment p is defined as the product of the magnitude of one of the charges and the distance separating them (2a). The direction of the dipole moment vector is from the negative charge to the positive charge. Given: q = 2.5 × 10⁻⁷ C Location of q_A (+q) is A(0, 0, -15 cm) Location of q_B (-q) is B(0, 0, +15 cm) The distance between them is 2a = 15 - (-15) = 30 cm = 0.3 m. Magnitude p = q × 2a = (2.5 × 10⁻⁷ C) × (0.3 m) = 0.75 × 10⁻⁷ C-m = 7.5 × 10⁻⁸ C-m. Direction: The vector points from the negative charge q_B at (0, 0, +15) to the positive charge q_A at (0, 0, -15). Since B is at z = +15 and A is at z = -15, the direction is from positive z to negative z, i.e., along the negative z-axis. (See NCERT Physics Class 12, Exercise 1.9).