RRB Group-D Model Paper 19 with answers for online practice

The pressure is the force acting on a unit area.

​P=F/A ( P= Pressure, F= Force, A= Area)

S.I Unit: Pascal

Surface Tension is defined as the force acting normally on the unit area of the surface.

• Surface Tension is the force exerted by a liquid surface to reduce its surface area to a minimum value.
• It mainly occurs due to cohesion.
• The spherical shape of the raindrop is due to the surface tension.
• Insects can walk over the water surface due to the effect of surface tension.
• The surface tension of the water can be reduced by adding detergents to it.
• Surface tension is inversely proportional to the pressure.
• Surface tension is inversely proportional to the temperature.

Viscosity is the internal frictional force acting between parallel layers of a liquid.

Torque is the capability of rotating objects around a fixed axis.