Question

The electric potential (V ) and electric field (⃗ E) are closely related concepts in electrostatics. The electric field is a vector quantity that represents the

• A. Production of AC is economical.
• B. AC can be easily and efficiently converted from one voltage to another.
• C. AC can be transmitted economically over long distances.
• D. AC is less dangerous.

Hint:

Key advantages of AC over DC: - Easy voltage transformation - Efficient long-distance transmission But safety depends on voltage and current, not just AC vs DC.

Answer 1

The Correct Option is D

Concept: AC (Alternating Current) has several practical advantages over DC (Direct Current):

Easy voltage transformation using transformers
Efficient long-distance transmission
Economical generation
However, safety depends on magnitude and conditions, not simply AC vs DC.
Step 1: Analyze each statement. (A) Production of AC is economical. True. AC generators are simpler and cheaper compared to DC generators. (B) AC can be easily converted from one voltage to another. True. Transformers work only with AC, allowing efficient voltage stepping up/down. (C) AC can be transmitted economically over long distances. True. High-voltage AC transmission reduces power loss (\( I^2R \) losses). (D) AC is less dangerous. Not necessarily true. In fact, AC can be more dangerous than DC at the same voltage because:

Causes continuous muscle contraction
Interferes with heart rhythm (50–60 Hz range)

Step 2: Conclusion. The incorrect statement is that AC is less dangerous.

Answer 2

Each statement claims something about alternating current (AC). Let's check each one against how AC actually behaves in generation, distribution, and safety.

1. Production of AC is economical: AC generators (alternators) have a comparatively simple rotating design and don't need the commutators and brushes that DC generators require, which keeps their construction and maintenance cost lower. This statement holds up.
2. AC can be easily and efficiently converted from one voltage to another: Because AC's magnitude varies with time, it can pass through a transformer, which works purely by electromagnetic induction between coils, to step voltage up or down with very little energy loss. DC cannot do this directly. This statement holds up.
3. AC can be transmitted economically over long distances: Since AC voltage can be stepped up to very high levels before transmission, the current for a given power is much smaller, and since resistive power loss scales as \( I^2R \), a smaller current means far less power wasted as heat over long transmission lines. This statement holds up.
4. AC is less dangerous: Danger from electric shock depends mainly on the current's magnitude and the path it takes through the body, not simply on whether the supply is AC or DC. In fact, AC in the household frequency range is generally considered more hazardous than DC at a comparable voltage, because it causes sustained muscle contraction and can disrupt the heart's own rhythm. This statement does not hold up.

Three of the four statements describe genuine, well-established practical benefits of AC, generation cost, easy voltage transformation, and efficient long-distance transmission. The claim that AC is inherently "less dangerous," however, does not reflect how AC and DC actually compare in terms of shock hazard.

Therefore, the correct answer is AC is less dangerous.