I recently appeared on my local TV station. When I arrived at the studio I was asked to change my shirt because its pattern would look distorted on screen. What causes this effect and why, in this day and age, is it impossible for television to simply record what is in front of the cameras?Alan Francis, Cardiff, UK

If electricity can be generated by moving a coil through a magnetic field, why do we not launch large coils into orbit? As they circled Earth within the planet’s magnetic field, the energy could be sent down from the coils via microwave: even people in remote areas could receive it. I suspect that this system would cost much less than energy generation does at present. So tell me, what flaws in this scheme would prevent me from picking up my Nobel prize?Robert Burns, London, UK