142. Larger buildings may be supplied with a medium voltage electricity supply, and will required a substation or mini-sub. What is the main item of equipment contained in these?

A. Transformer
B. Transponder
C. Transducer
D. Converter
✅ The correct answer is option A.
The transformer is used to transform a medium voltage supply to a low voltage supply, e.g. from 11 000 V to 400 V. A transformer is rated in KVA, kilo-Volt-Amps, which is a measurement of electrical power.

149. The IBM PC-XT was the first to include a hard drive. What was the capacity of this disk?

A. 20 MB
B. 1.44 MB
C. 10 MB
D. 750 KB
✅ The correct answer is option C.
The original IBM PC used 5.25-inch floppy disks to store its operating system and programs. IBM referred to the new hard disk as a Fixed Disk. Today, even a the operating system wont fit on a 10 MB disk.

150. In which decade was the telephone invented?

A. 1850s
B. 1860s
C. 1870s
D. 1880s
✅ The correct answer is option C.
Alexander Graham Bell’s notebook entry of 10 March 1876 describes his successful experiment with the telephone. Speaking through the instrument to his assistant, Thomas A. Watson, in the next room, Bell utters these famous first words, “Mr. Watson — come here — I want to see you”.