Sticking electromagnetic grenades and bombs

Sticking electromagnetic grenades and bombs for against tanks and other armoured vehicles.
-It's so that the bomb or grenade will not roll or drop off the tank or other armoured vehicle.

With an on and off switch for the electromagnet.
And a pin for the grenade or bomb for example.

Important: First safe tests. There might be a problem, and it could be solvable if so.

Extra: Primitive versions do exist using sticking substances.