A cantilever beam of uniform EI has span equal to 'L'. An upward force W acts at the mid-point of the beam and a downward force P acts at the free end. In order that the deflection at the free end is zero, the relation between P and W should be

In trigonometric levelling, if the horizontal distance between the instrument and the object is 3088 m, the coefficient of refraction is 0.07 and R sin 1" = 30.88 m, then the refraction correction in angular measure would be