An α-particle of mass 6.6×10−27kg is moving at 2.0×105ms−1 towards a stationary gold nucleus of mass 3.3×10−25kg. After a perfectly inelastic head-on collision, the two stick together. Calculate the de Broglie wavelength of the combined system immediately after the collision.
a) 0.20pm
b) 0.50pm
c) 5.0pm
d) 0.05pm