To solve the question "In a standing wave, node is a point of", we need to analyze the characteristics of nodes in standing waves. Here’s a step-by-step solution:
### Step 1: Understand the Concept of Standing Waves
A standing wave is formed by the superposition of two waves traveling in opposite directions. It consists of nodes and antinodes. Nodes are points where there is no displacement, while antinodes are points of maximum displacement.
**Hint:** Recall that nodes are points of no movement in a standing wave.
### Step 2: Define a Node
At a node, the displacement of the medium is always zero. This means that the particles at the node do not oscillate; they remain stationary.
**Hint:** Think about what happens to particles at a node in terms of their motion.
### Step 3: Analyze Pressure Variation
In a standing wave, the pressure variation is related to the displacement. At a node (where displacement is zero), the pressure variation is at a maximum. This is because when particles are at rest, they are compressed, leading to higher pressure.
**Hint:** Consider the relationship between displacement and pressure in wave mechanics.
### Step 4: Consider Density
Density is also affected by pressure. According to the principles of fluid dynamics, when pressure increases, the density of the medium also increases. Therefore, at a node, where pressure is maximum, the density will also be maximum.
**Hint:** Reflect on how pressure and density are related in a compressible medium.
### Step 5: Strain in the Medium
Strain is a measure of deformation representing the displacement between particles in a material body. At a node, since the particles are compressed and not moving, the strain is also at its maximum.
**Hint:** Think about how strain relates to the movement of particles in a wave.
### Conclusion
Thus, at a node in a standing wave, we find that:
- The displacement is zero.
- The pressure is at a maximum.
- The density is at a maximum.
- The strain is also at a maximum.
Therefore, the correct answer to the question is that a node is a point of maximum strain, maximum pressure, and maximum density.
**Final Answer:** All of the above (maximum strain, maximum pressure, maximum density).
