Answer (b) \(48 \,cm \,s^{-1}\)
According to the equation of continuity, Av are constant.
So, $A_1v_1 = A_2 v_2$
$\frac{\pi \times d_1 ^2}{4}V_1= \frac{\pi \times d_2 ^2}{4}V_2$
$V_2 = V_1.(\frac{d_1 }{d_1 })^2$
$V_2 = 3.(\frac{2}{0.5})^2$
$V_2 = 48 cm/s$
So, The speed of water emerging from the nozzle is 48 cm
In fluid dynamics, Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluid's potential energy. The principle is named after Daniel Bernoulli who published it in his book Hydrodynamica in 1738.