A thin liquid film formed between a U-shaped wire and a light slider supports a weight of $1.5 \times 10^{-2}N$ (see figure). The length of the slider is 30 cm and its weight negligible. The surface tension of the liquid film is <br>

Question

( A ) $0.1\; Nm^{-1}$
( B ) $0.0125\; Nm^{-1}$
( C ) $0.05\; Nm^{-1}$
( D ) $0.025\; Nm^{-1}$