stroke - How do I make a ray effect in Illustrator?

What I've been doing is copied each stroke, selecting the end anchor point and moving it using the arrow keys:

Is there an easier way to do the following "semi-circle ray effect" in Illustrator?

Answer

A quick and easy way... use a Transform effect (Effect → Distort & Transform → Transform...) on a single line, setting an appropriate number of copies and rotation angle^*. Set the transform origin to the edge which you want to be the center of the "ray"...

^*Quick tip: you can do basic math in the angle input; so if you want 10 rays over 180 degrees, you input 180/10, and it will set the correct angle for you.

If you want varying line lengths you can create a single line for each different length with a Transform effect on each, adjusting the rotation angle and number of copies as needed...