can't make 2d ball jump on the same distance every time

hello !

I can't make 2d ball jump on the same distance every time. I don't want it to have bounciness , in my script when i click mouse button it jumps normally but when I play game on phone ball jumping way to high.

void FixedUpdate ()
{
if (CanJump == true ) {
if (Input.GetMouseButtonDown (0))
{
rb.velocity = new Vector2 (rb.velocity.x + speed,rb.velocity.y + JumpForce);
}
}
}