Concept:Cathode rays travel in straight lines, so they cannot bend around an obstacle to reach the shadow region.
Explanation:Cathode rays are streams of electrons emitted from the cathode.
When an object is placed behind a perforated anode, it blocks the rays travelling in a straight path.
The region behind the object receives no rays, so a shadow is formed on the screen.
This happens because the rays move in straight lines and do not curve around the object.
The shadow is not due to charge or mass, but due to the linear path of the rays.
Answer:D. travel in straight lines