Two charges of -4μC and +4μC are placed at the points A(1,0,4)m and B(2,−1,5)m located in an electric field E→=0.20i^V/cm. The magnitude of the torque acting on the dipole is 8α×10-5Nm, where α = _________. [2024]
(2)
τ→=p→×E→
p→=qℓ→
E→=0.2i^Vcm=20i^Vm
p→=4×(i^-j^+k^)=(4i^-4j^+4k^) μC-m
τ→=(4i^-4j^+4k^)×(20i^)×10-6 Nm
=(8k^+8j^)×10-5⇒|τ→|=82×10-5