Q.

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]


Ans.

(2)

τ=p×E

p=q

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

alpha equals 2