Match the slab conditions in List I with List II.

List 1

1. P. Normal incidence

2. Q. Parallel faces, same surroundings

3. R. Thickness doubled

4. S. μ of slab equals surroundings

List 2

1. 1. 1. Zero shift

2. 1. 2. Emergent ray parallel

3. 1. 3. Shift doubles

4. 4. 4. No refraction