Question

The difference between pressure and stress is
(A) Pressure and stress have different units
(B) Pressure and stress have different dimensions
(C) Force cannot be determined using stress, but in pressure can be done
(D) Pressured is applied to a body, while stress is induced

Answer 1

Hint
The pressure is the force's effect in the unit area, and the stress is the internal resisting force applied by the unit area of the object. The object deforms by the stress's effect, but pressure does not consider the object's deformation. The component of the force that is normal to the surface of the object evaluates the pressure. The stress can only be evaluated; it cannot be measured while the pressure can be calculated and measured by using the pressure measuring devices like pressure gauge, manometers, etc.

Complete step by step answer
Let us assume that we are trying to insert a nail into any surface. When we apply the small amount of force on the nail, then the nail makes an impression on the object's surface. If we increase the amount of the force on the nail, then the nail is inserted into the surface. It happens because of the effect of the applied force on the surface of the object. The area of the nail and the applied force are the deciding factors that measure the force's effect in the area, equal to the area of the tip of the nail. If the nail area increases, then the large force is necessary to insert the nail into the surface of the object.
When the external force applies to the object, the object's surface deforms due to its effect. If the applied force is removed from the object's surface, the body returns to its previous position. It happens because an equal amount of applied force acts opposite to the applied force. The opposing force applied by the object resists the deformation of the object. The effect of the object's resisting force in a certain area of the object is called stress.
Therefore, option (D) is correct.

Note
The pressure is the effect of the applied force, but the stress is the effect of the object's resisting force. Always remember that the stress is related to the object's deformation, but the pressure is associated with the effect of the force only. The effect of the stress depends on the nature of the object's material, but the pressure is independent of the nature of the object's material.