The following statements relate to a laminar flow :
1. Laminar flow is rotational.
2. In laminar flow the loss of head is proportional to the square of the velocity.
3. In laminar flow the loss of head is proportional to the first power of viscosity.
4. In laminar flow the velocity is constant over the cross-section.
5. Other quantities remaining the same, increase in diameter will increase the Reynolds number in laminar flow.
Of these statements :