The machines have various elaborate mechanisms for gauging a coin’s exact dimensions and weight, channelling bogus ones to the device’s return tray. Coins are also passed through a magnetic field. An individual coin’s own magnetic properties determine its path and speed through the sensors, thus sorting counterfeit from credible. While fraudsters can mimic superficial surface properties of coins, it’s virtually impossible to blend metals to achieve such exacting magnetic properties.
Answered by Gareth Mitchell
.jpg)
More about BBC Worldwide.
Diverse thinkers, from the ancient Greek philosophers through contemporary quantum cosmology and eternal inflation theory, have called time an illusion. For them, the perception of time passing...
Air crash investigators have found that flight stewards in rear-facing seats have suffered less severe injuries in accidents than forward-facing passengers. This is because the energy from the...
While Britons have pioneered all sorts of things from the steam engine and the computer to passenger jets and rugby football, we have dismally failed to maintain world dominance in much at all...
Ordinary glass absorbs 97 per cent of the UVB rays that cause sunburn and some skin cancers, and 37 per cent of the less harmful UVA radiation. This translates to a protection of about SPF30, so...
The ice disappears because the wind blows away water molecules that have evaporated or 'sublimed' from the ice, so the ice slowly shrinks in size. The molecules that escape are those with the...