42W Bulb: Calculate Current Draw? Quiz Practice…

Q: What is the primary formula used to calculate current (I) in a circuit, given power (P) and voltage (V)?

I = P / V — Current is directly proportional to power and inversely proportional to voltage.

Q: A 42W light bulb is connected to a 12V DC power source. What is the current draw?

3.5 A — Using I = P/V, 42W / 12V = 3.5A

Q: If a 42W bulb is connected to a 120V AC power source, how would you calculate the current?

I = P / V — The formula remains the same regardless of AC or DC: I = P/V.

Q: What is the unit of measurement for electric current?

Ampere (A) — Current is measured in Amperes (A).

Q: What is the standard voltage rating in North America for household AC power?

120 V — 120V is the standard nominal voltage.

Q: Calculate the current drawn by a 42W bulb connected to a 240V AC power source.

0.175 A — Using I=P/V, 42W / 240V = 0.175 A

Q: What happens to the current draw if the voltage increases while the power rating of the bulb remains constant?

The current decreases. — I = P/V, so current is inversely proportional to voltage.

Q: If a 42W bulb is connected in series with a resistor, will the current draw of the bulb change compared to being connected directly to the voltage source?

Yes, it will decrease. — A series resistor reduces the voltage across the bulb, reducing current.

Q: Which of the following is the correct unit for power?

Watt — Power is measured in Watts (W).

Q: Why is it important to know the current draw of a bulb?

All of the above. — Knowing the current draw is critical for safety and circuit design.

Question 1 of 10

What is the primary formula used to calculate current (I) in a circuit, given power (P) and voltage (V)?

Current is directly proportional to power and inversely proportional to voltage.

Question 2 of 10

A 42W light bulb is connected to a 12V DC power source. What is the current draw?

Using I = P/V, 42W / 12V = 3.5A

Question 3 of 10

If a 42W bulb is connected to a 120V AC power source, how would you calculate the current?

The formula remains the same regardless of AC or DC: I = P/V.

Question 4 of 10

What is the unit of measurement for electric current?

Current is measured in Amperes (A).

Question 5 of 10

What is the standard voltage rating in North America for household AC power?

120V is the standard nominal voltage.

Question 6 of 10

Calculate the current drawn by a 42W bulb connected to a 240V AC power source.

Using I=P/V, 42W / 240V = 0.175 A

Question 7 of 10

What happens to the current draw if the voltage increases while the power rating of the bulb remains constant?

I = P/V, so current is inversely proportional to voltage.

Question 8 of 10

If a 42W bulb is connected in series with a resistor, will the current draw of the bulb change compared to being connected directly to the voltage source?

A series resistor reduces the voltage across the bulb, reducing current.

Question 9 of 10

Which of the following is the correct unit for power?

Power is measured in Watts (W).

Question 10 of 10

Why is it important to know the current draw of a bulb?

Knowing the current draw is critical for safety and circuit design.

42W Bulb: Calculate Current Draw? Quiz