The Theory Test is made up of two parts; the multiple choice and the hazard perception part. 

You will need to pass both parts to pass the theory test. Once you have passed the theory test you can then apply for your practical test, but you must make sure that you  have had sufficient driving practice, to ensure that you are ready for the practical test before you apply.

The multiple choice part of the test consists of 50 multiple choice questions.

From September 2009 5 of these questions will be based on certain scenarios which focus on real life examples and experiences that you might encounter when out driving.

 The pass mark for the multiple choice part is 43 out of 50.

The hazard perception part of the test is done on computer. You respond by clicking on the mouse. You will have a series of 14 video clips which feature every day road scenes.

 Each clip will have at least one developing hazard, but one clip will have two. To achieve a good score you need to respond to the developing hazard during the early part of the clip.

 The maximum score for each clip is 5 points. You cannot review your answers to the hazard perception test, as on the road you will only have one chance to respond to a developing hazard.

The pass mark for the car hazard perception part is 44 out of 75.

Check this out. Official car theory test.