Electro Magnetic Pulse (EMP) has no effect on man but can damage electrical and communication equipments. In a ground nuclear explosion, sand and dust are sucked by the fireball and become radioactive. It will form fall out for a long time.

Gamma rays ionise atmospheric gases, thus disrupting communication. EMP vary from few hundred Hz to several MHz with an electric field intensity of 50 kV/m, which can cause damage semiconductor devices, insulation failure in cables, direct damage to equipment, corruption of data in magnetic storage, Radars of MF and UHF (large aperture antenna), ignite petrol vapour and explosives etc.

Radar and radio are blacked out for short or long periods due to ionisation of the atmosphere. Radar can create a field intensity of 200 V/m.

In Radar, a transmitted signal is received after 2 ms, the target is at a distance of 300 km. Wave guides (metal pipes of specific dimension) are used for high frequencies.