Which of these is incorrect about nuclear forces ?

Options

A. they are independent of charge
B. Nuclear forces are derived from quark-quark interaction
C. Hadrons do not experience strong nuclear force
D. Nuclear force is not a central force

Answer

To determine which statement about nuclear forces is incorrect, we need to analyze the properties and characteristics of nuclear forces. Here’s a step-by-step solution:

### Step 1: Understand Nuclear Forces
Nuclear forces are the interactions that occur between nucleons (protons and neutrons) within an atomic nucleus. These forces are responsible for holding the nucleus together despite the repulsive electromagnetic forces between the positively charged protons.

**Hint:** Recall that nuclear forces act between protons and neutrons, and they are essential for the stability of the nucleus.

### Step 2: Identify Types of Nuclear Forces
Nuclear forces can be classified as strong nuclear forces, which are attractive and act at very short ranges (on the order of 1 femtometer or 10^-15 meters). They are much stronger than electromagnetic forces but only act over very short distances.

**Hint:** Remember that strong nuclear forces are attractive at short distances and are crucial for binding nucleons together.

### Step 3: Analyze the Statements
1. **Nuclear forces are independent of charge**: This statement is correct because nuclear forces act between all nucleons regardless of their charge (neutrons and protons).

2. **Nuclear forces are derived from quark-quark interactions**: This statement is also correct as nucleons are made of quarks, and the interactions between these quarks give rise to nuclear forces.

3. **Nuclear forces are repulsive if the distance is less than 0.7 femtometers**: This statement is incorrect. While nuclear forces can become repulsive at very short distances, they are primarily attractive at distances greater than about 0.7 femtometers. The repulsive nature at very short distances is a characteristic of the strong force, but it does not dominate the interaction until extremely short ranges.

**Hint:** Consider the behavior of forces at very short distances and how they change from attractive to repulsive.

### Step 4: Conclusion
The incorrect statement about nuclear forces is the third one, which suggests that nuclear forces are repulsive at distances less than 0.7 femtometers.

**Final Answer:** The third statement is incorrect about nuclear forces.