Answer:
150°
Step-by-step explanation:
It is given that CosФ < 0 i.e CosФ is negative.
Therefore, the minimum the value of Ф for which CosФ <0 will be in the second quadrant i.e 90° < Ф < 180°.
Now it is also given that, Sin Ф =0.5 {the value of SinФ is positive because Sin value is positive in second quadrant.}
⇒ Ф =180° - Sin⁻¹ (0.5) = 180°-30° =150° (Answer)
