According to the Bernoulli's equation,the pressure difference between the wide and narrow ends of the pipe is given by

Here,
is the velocity of water through wide ends of cylindrical pipe and
is the velocity of water through narrow ends of cylindrical pipe.
Given, 
Now from equation continuity,
.
Here,
and
are cross- sectional areas of wide and narrow ends of cylindrical pipe.
As pipe is circular, so
.
At the second point, the diameter is halved, which means the radius is also halved. Therefore,


Substituting these values with the density of water is
in pressure difference formula we get.

Answer:
I = 0.2 A
Explanation:
Lamp is rated at 300 mA
I_lamp = 0.3 A
Voltage is; V = 3V
Thus; Resistance is given by;
R = V/I
R = 3/0.3
R = 10 ohms
Now, since the ammeter of 5 ohms is connected in series with the lamp. Thus equivalent resistance;
R_eq = 10 + 5
R_eq = 15 ohms
Ammeter current will be;
I = V/R_eq
I = 3/15
I = 0.2 A
Answer:
The fundamental wavelength of the vibrating string is 1.7 m.
Explanation:
We have,
Velocity of wave on a guitar string is 344 m/s
Length of the guitar string is 85 cm or 0.85 m
It is required to find the fundamental wavelength of the vibrating string. The fundamental frequency on the string is given by :

Now fundamental wavelength is :

So, the fundamental wavelength of the vibrating string is 1.7 m.