Q. Which river separates Kaimur hills from Chota Nagpur plateau?
Answer: North Koel
Notes: The North Koel River separates the Kaimur hills from the Chota Nagpur plateau in Jharkhand. The Son River forms the northwestern boundary of the plateau. The North Koel flows through east-west hills, creating a divide between southern Kaimur hills and northern Chota Nagpur plateau. The South Koel flows within the plateau. The Falgu River is near Gaya, and the Kiul River flows through Bihar plains, so they do not separate these areas.