If the object is between infinity and the center of curvature in front of a concave mirror, the image formed is _______.   erect   diminished   virtual   Hint Half-n-half Clue   Light rays that pass or appear to pass through the _______ are reflected by the curved mirror parallel to the principal axis.   pole   center of curvature   principal focus   Half-n-half Clue   If the focal length of a spherical mirror is 50 cm, then its radius of curvature is _______ cm.   50   100   25   Half-n-half Clue   Light rays parallel to the principal axis are reflected by the curved mirror through the _______.   principal focus   pole   center of curvature   Half-n-half Clue   A concave mirror has a _______ principal focus.   virtual   real