Yes, you will almost certainly be electrocuted if you throw a rope onto a high-voltage power line. The rope itself doesn't need to directly contact the line to cause electrocution. The high voltage will arc across a gap, jumping from the power line to the rope (and then likely to you, if you are holding the rope). The length of the arc depends on the voltage; higher voltages can jump a larger gap.
Even if you throw the rope and let go, the arc could still occur, and the current could flow through the rope, the ground, and potentially back to the power line. Do not attempt this under any circumstances. High-voltage power lines are extremely dangerous.
