As shown, a $110\,\text{V}$ d.c. supply is linked to a heater, a fuse and a switch. Because of a fault in the circuit, the heater does not receive power. A technician uses a voltmeter to find the fault. He then closes the switch and attaches his meter between the positive supply terminal $\text{S}^+$ and the fuse terminal $\text{F2}$. The voltmeter gives a reading of $110\,\text{V}$. Which diagnosis is the correct one?
- AThe fuse has melted.
- BThe fuse has not melted and there is a short circuit in the heater.
- CThe fuse has not melted and there is no path for current through the heater.
- DThe fuse has not melted and the switch has operated correctly.