Hello, Hopefully I can help.
2011 Q12:
the positive particles will travel from the plus on the power source to the left and then past X then Y and then complete the circuit. Therefore, use your right hand at the coil next to X to grip in the direction that the particles are flowing (i.e. your grip should be with your thumb to the left). Therefore, there is a north where your thumb is and a south on the other side, (i.e. the area where the X is, is a south pole). Therefore it must be either A or B. Then you just use you right hand palm rule (fingers should be pointing to the left and thumb towards you) to find the direction of the motion of Y which will leave the answer as A.
2010 Q20:
The answer must be either A or B since the two magnets are opposites (i.e. a north and a south) you can determine this by using the right hand grip rule to follow the path of the positive particles with your fingers. In B, the left electromagnet is a south inward and the right one is a north inward. Therefore your magnetic field is from right to left. and lets take the left side of the coil, the positive current is flowing from the bottom to the top of the page. Therefore position your right hand palm rule to satisfy these things and you will determine that the force is upwards therefore the rotor with turn in a clockwise direction. Therefore the answer is B.
Cya
