An electron gun in a cathode-ray tube contains a heated cathode and an anode. Which row in the table correctly identifies the process by which electrons are released from the cathode, and the charge on the accelerating anode?
| Process of electron release | Charge on the anode | |
|---|---|---|
| A | photoelectric emission | negative |
| B | photoelectric emission | positive |
| C | thermionic emission | negative |
| D | thermionic emission | positive |
Process: photoelectric emission; Charge: negative
Process: photoelectric emission; Charge: positive
Process: thermionic emission; Charge: negative
Process: thermionic emission; Charge: positive
136 exam-style questions on CIE IGCSE Physics 4.3 Electric circuits, covering 4.3.1a Circuit diagrams and circuit components, 4.3.2a Series circuits, 4.3.2b Parallel circuits, 4.3.2c Current and potential difference in circuits, 4.3.2d Combined resistance of resistors in parallel, and 4.3.3 Action and use of circuit components. Each one has a worked solution and a mark scheme showing where the marks go.