A straight conductor of length 0.20 m carries a current of 5 A in a uniform magnetic field of 0.4 T. The conductor initially makes an angle of 30° with the field. It is then rotated so that the angle becomes 60°, all other quantities remaining unchanged. The force on the conductor after rotation is
a) 31 times its initial value
b) 3 times its initial value
c) equal to its initial value
d) twice its initial value