When cathode rays, which are negatively charged particles (electrons), are emitted from the cathode in a cathode ray tube, the law of conservation of charge must be taken into account. According to this law, the total electric charge in an isolated system remains constant. Therefore, if negative charges are emitted from the cathode, there must be an equal amount of positive charge somewhere in the system to balance it out.

In a cathode ray tube, the positive charges that balance the negative charges of the cathode rays are located on the anode. The anode is a positively charged electrode placed at the opposite end of the tube from the cathode. The positive charges on the anode attract the negatively charged cathode rays, causing them to accelerate across the tube and strike the fluorescent screen at the other end.

The positive charges on the anode are typically created by connecting the anode to a high-voltage power supply. This causes electrons to be stripped from atoms in the anode material, creating positively charged ions. The positive ions are then attracted to the negative charges on the cathode, completing the circuit and allowing the cathode rays to flow.

In summary, when cathode rays (negative charges) are emitted from the cathode in a cathode ray tube, positive charges (ions) are created on the anode to balance the charges and maintain the overall neutrality of the system.