13. Before working on a circuit, you must______
the power supply.
a.switch on
b.switch oft
c.hold
d.throw
14. The goal of controlling hazards is to prevent workers from being exposed to occupational hazard
a.true
b.false
c.maybe
d.none of the above
15. Personal protective equipment (PPE) should be the last choice in control measures.
a. true
b.false
c.maybe
d.none of the above
16. It is used to emit light when a current is passed through the device.
a.LED
b.LDR
c.resistor
d.transistor​