Assertion : The size of the needle of a syringe controls flow rate better than the thumb pressure exerted by a doctor while administering an injection.
Reason : Flow rate is independent of pressure exerted by the thumb of the doctor.

Explain why (a). To keep a piece of paper horizontal, you should blow over, not under, it (b). When w try to close a water tap with our fingers, fast jets of water gush through the openings between our fingers (c). The size of the needle of a syringe controls flow rate better than the thumb pressure exerted by a doctor while administering an injection (d). A fluid flowing out of a small hole in a vessel results in a backward thrust on the vessel (e). A spinning cricket ball in air does not follow a parabolic trajectory.

Assertion : The pressure at the bottom of the sea is lesser than that near the surface. Reason : The pressure exerted by a liquid depends upon the depth of the liquid and density of the liquid.

Which factor better controls the flow rate of a liquid throught the syringe?

Torricelli was the first do devise an experiment for measuring atmospheric pressure . He took calibrated hard glass tube , 1 m in lengt and of uniform cross section , closed at one end . He filled the whole tube with dry mercury taking care than no air or water droplets remain inside the tube , closed the opposite end of the tube tightly with thumb and inverted it . He put this inverted mercury tube into a mercury through , taking care that the end of the tube remains inside the mercury through , An interesting thing was noticed . Mercury in the tube fell down at first and then stopped at a particular position . The height was 76 cm above the free surface of mercury in the through . When the given tube was inclined or lowered in the mercury trough , the vertical haight of mercury level in the tube was always found constant . Torricelli explained this by saying that the free surface of mercury in the trough . Hence , the hydrostatic pressure exerted by the trough measures the atmospheric pressure . If an additional hole is also made at P ' at the top point of the tube , then

Torricelli was the first do devise an experiment for measuring atmospheric pressure . He took calibrated hard glass tube , 1 m in lengt and of uniform cross section , closed at one end . He filled the whole tube with dry mercury taking care than no air or water droplets remain inside the tube , closed the opposite end of the tube tightly with thumb and inverted it . He put this inverted mercury tube into a mercury through , taking care that the end of the tube remains inside the mercury through , An interesting thing was noticed . Mercury in the tube fell down at first and then stopped at a particular position . The height was 76 cm above the free surface of mercury in the through . When the given tube was inclined or lowered in the mercury trough , the vertical haight of mercury level in the tube was always found constant . Torricelli explained this by saying that the free surface of mercury in the trough . Hence , the hydrostatic pressure exerted by the trough measures the atmospheric pressure . If this expriment uses water instead of mercury , then

Assertion (A) : K_(p) is always greater than K_(c) . Reason (R) : The effect of pressure is greater on the rate of reaction than the effect of concentration.