Part 1 of Essay
You might remember the heroic role that newly-invented radar played in the Second World War. People hailed it then as "Our Miracle Ally". But even in its earliest years, as it was helping win the war, radar proved to be more than an expert enemy locator. Radar technicians, doodling away in their idle moments, found that t ....

Part 2 of Essay
.... beam with an antenna many times smaller. This enabled them to make more effective use of radar since an antenna could be carried on aircraft, ships and mobile ground stations. This characteristic of , the efficiency with which they are concentrated in a narrow beam, is one reason why they can be used in cooking. You can produce a high-powered microwave beam in a small oven, but you can't do the same with radio waves, which are simply too long. and their Use The idea of cooking with radiation may seem like a ....