Correct Option
The correct option is 1 and 3 only.
Explanation
Ocean currents represent the continuous, predictable, directional movement of seawater driven by gravity, wind (Coriolis Effect), and water density. They are broadly categorized into surface currents and deep-water currents based on the depth at which they flow.
Statement-wise Analysis
- Statement 1 is Correct: In the context of oceanography, the intensity or power of a current is determined by its velocity. Consequently, a current moving with high velocity is characterized as a "strong" current.
- Statement 2 is Incorrect: Deep ocean currents are primarily driven by density differences (thermohaline circulation) rather than wind. These currents are voluminous but move extremely slowly, often at speeds of a few centimeters per second. In contrast, strong surface currents like the Gulf Stream may reach speeds of 3 to 5 knots. It is factually incorrect to state that deep currents generally exceed 5 knots.
- Statement 3 is Correct: The terminology used to describe the physical properties of a current includes its "set" (direction) and "drift" (speed). The strength of the current is a direct reference to its speed (drift).
Key Takeaway
Surface currents are wind-driven and faster, while deep ocean currents are density-driven and extremely slow. The strength of a current is defined by its speed, not its depth.