Q1: The viscosity of water at room temperature may be around one

ANS:A - centipoise

The viscosity of water at room temperature is approximately 1 centipoise (cP). While both poise (P) and stoke (St) are units used to measure viscosity, centipoise is the most commonly used unit for measuring the viscosity of liquids like water. So, the correct answer is (a) centipoise. Centipoise (cP) is a unit of dynamic viscosity commonly used to measure the resistance of a fluid to flow. It is a derived unit in the centimeter-gram-second (CGS) system of units. Dynamic viscosity represents the internal friction of a fluid and is defined as the force required to move one layer of fluid in relation to another layer, divided by the area and velocity gradient between the two layers. In simpler terms, it quantifies how easily a fluid flows when subjected to an external force. The prefix "centi-" in centipoise means one one-hundredth, so one centipoise is equal to one hundredth of a poise (1 cP = 0.01 P). Since the poise is a relatively large unit, centipoise is often used for measuring the viscosity of common fluids like water, oils, and other liquids. For example, water at room temperature (approximately 20°C or 68°F) has a viscosity of about 1 centipoise, which means it flows relatively easily compared to more viscous fluids like oils. This low viscosity is one reason why water is often used as a standard reference fluid in viscosity measurements and comparisons.