Dear Mr. Surendra Singh,
Psychometric tests as the name suggests is the test to measure one's psychology/attitude. The set of questions will be like this. The first set of questions will be asked to know wherein you will choose a strict yes/no. The same questions are repeated somewhere later with little deviation and a wide range of possible answers are provided. in other words the answers will range from 1. sometimes yes 2. sometimes no besides yes and no to the question. Again the same is question is repeated with more deviation and the answers are provided. Answering the same question at different times differently will provide a picture upon your psychology/attitude and a measure of your integrity.
Although most of the times these are used during the appraisal process, off late these are being used during the recruitment process only to understand the attitude of the candidate. These are at present not being considered for the rejection of the candidature, however, during appraisals the responses are highly evaluated to elevate a person to the next level.
Ramasastry