# MCQs on Basic Electrical Quantities [Power, Voltage, Current, Resistance]

Electrical and Electronics Engineering is the branch of Engineering which deals with the generation, transmission, and distribution of electricity. It also involves the study of electronic components which utilize this electricity. The study of electricity is based on four basic properties: voltage, current, resistance, and power. Given below are the top 10 MCQs on basic properties, their SI units, and formulas with solved examples.

1. SI unit of current is:

1. Amps
2. Volts
3. Watts
4. Ohms

2. SI unit of power is:

1. Amps
2. Volts
3. Watts
4. Ohms

3. A 0.5 watt resistor can bear how many amps when connected to 12 volt source:

1. 0.5 amps
2. 0.009 amps
3. 0.04 amps
4. 6 amps

I = P/V = 0.5 watts/12 volts = 0.04 amps

4. 2 Coulombs of charge passing through a wire for 3 seconds will produce amps:

1. 6 amps
2. 0.6 amps
3. 1.5 amps
4. 5 amps

I = Q/t = 2 coulombs / 3 seconds = 0.6 amps

5. 50 joules of energy is needed to move a 2 C charge from one point to another. The potential difference between points is:

1. 1 volt
2. 25 volts
3. 50 volts
4. 100 volts

V = W/Q = 50 J/ 2C = 25 volts

6. Current flowing through a 10 ohms resistor when subject to 12 volts is:

1. 0.83 A
2. 1 A
3. 1.2 A
4. 120 A

I = V/R = 12 V/10 ohms = 1.2 Amps

7. The wattage rating of resistor which takes 2 Amps of current when a voltage sources of 230 volts is applied to it:

1. 115 watts
2. 230 watts
3. 460 watts
4. 1000 watts

P = V.I = 230 volts * 2 Amps = 460 watts

8. The resistance of 3 m copper wire having area of 2 * 10-6 m2 is:

1. 0.1 Ω
2. 0.01 Ω
3. 0.2 Ω
4. 0.02 Ω

Using formula: R = ρ.l/a;

For copper ρ = 1.732 * 10-8 Ω-m

R = ( 1.732 * 10-8 Ω-m * 3 m) / ( 2 * 10-6 m2 )

= 0.02598 = 0.02 ohms

9. The energy required to move 5 C of charge through a lamp having a potential difference of 20 volts applied across it:

1. 4 J
2. 10 J
3. 50 J
4. 100 J

W = V*Q = 20 V * 5 C = 100 J

10. A 20 ohms resistance posses conductance of:

1. 20 S
2. 100 S
3. 0.05 S
4. 0.025 S