IST Electrical and Electronic Knowledge

Question 1

What is the standard unit of measurement for electrical resistance?

Accepted Answer

Ohm

Answer

Electrical resistance is measured in Ohms, named after German physicist Georg Ohm.

Question 2

According to Ohm's Law, if voltage is 120V and resistance is 30 Ohms, what is the current?

Accepted Answer

4 A

Answer

Ohm's Law: Current (I) = Voltage (V) ÷ Resistance (R) = 120 ÷ 30 = 4 Amps.

Question 3

What color is the standard neutral wire in US residential and light commercial wiring?

Accepted Answer

White or gray

Answer

White or gray wires are the standard colors for neutral conductors in US electrical wiring.

Question 4

What device is used to protect an electrical circuit from damage caused by excess current?

Accepted Answer

Fuse or circuit breaker

Answer

Fuses and circuit breakers protect circuits by interrupting the flow of current when it exceeds a safe level.

Question 5

What is the purpose of a ground wire in an electrical circuit?

Accepted Answer

To provide a safe path for fault current

Answer

The ground wire provides a safe low-resistance path for fault current, protecting people from electric shock.

IST - Industrial Skills Test Practice Test