Ans:- Digital computers were invented for performing long, time consuming scientific calculation quickly. Today’s fast computers can create and display virtual reality scenarios on the computer monitor. Scientists use simulations to test scientific theories’ as well as to perform risky experiment’s, such as those involving explosive or toxic materials. A flight simulator is now invariably used to teach trainee pilots various controls of an aeroplane. This allows the trainee to practise all the controls under normal as well as emergency situation before actually flying a plane, thus minimising the risk of loss of life and property.