Home
Class 12
PHYSICS
Mercury flows at a speed of 20 cm/s in a...

Mercury flows at a speed of 20 cm/s in a pipe with conducting walls of 5 cm diameter. The pipe is in the gap between the pole pieces of an electromagnet, the magnetic field in the gap having induction of 0.6 T. Will the magnetic field affect the hydraulic friction coefficient? The conductivity of mercury is `10^(6)ohm^(-1).m^(-1)`.

Text Solution

Verified by Experts

The correct Answer is:
It will [Hint. Find the Stewart number]
First find the Reynolds number.
`Re=(rhovl)/(eta)=(13.6xx10^(3)xx5xx10^(-2)xx0.2)/(1.55x10^(-3))=8.8xx10^(4)gtgt2300`.
Hence the flow is turbulent and it should be assessed with the aid of the Stewart number:
`N=(gammaB^(2)l)/(rhov)=(1.05xx10^(6)xx0.36xx5xx10^(-2))/(13.6xx10^(3)xx0.2)=7`
But the Stewart number represents the ratio of the magnetic force to the resistance of pressure. Hence, in this case the magnetic force will appreciably affect the coefficient of hydraulic friction.
Promotional Banner

Similar Questions

Explore conceptually related problems

A small piece of wire is passed through the gap between the poles of a magnet in 0.1 sec. An e.m.f. of 4 xx 10^(​–8) ​volts is induced in the wire. The magnetic flux between the poles (in weber) is:

The amplitude of the electric field of a plane electromagnetic wave in air is 6.0 xx 10 ^(-4) V m ^(-1). The amplitude of the magnetic field will be

A rectangular loop of sides 10cm and 5cm with a cut is stationary between the pole pieces of an electromagnet. The amgnetic field of the magnet is normal to the loop. The current feeding the electromagnet is reduced so that the field decreases from its initial value of 3.0 T at the rate of 0.02 T s^(-1) . If the cut is joined and the loop has a resistance of 2.0 Omega , the power dissipated by the loop as heat is

A straight wire of length 0.5 m carrying a current of 1.6 ampere is placed in a uniform magnetic field of induction 2 T. If the magnetic field is perendicular to the length of the wire, then force on the wire is

A circular disc of radius 20 cm is rotating with a constant angular speed of 2.0 rad//s in a uniform magnetic field of 0.2 T. Find the e.m.f. induced between the centre and rim of the disc. Given magnetic field is along the axis of rotation of disc.

A condenser has two conducting plates of radius 10cm separated by a distance of 5 mm . It is charged with a constant current of 0.15A . The magnetic field at a point 2cm from the axis in the gap is

A long conducting wire of radius 1 cm carrying current of 1 A placed with its axis coinciding with X-axis. Find the magnetic field at point having coordinates (0.5 cm, 0.5 cm ) .

A conducting wire of length 10 cm is moving perpendicular in a region of magnetic field 1 tesla with a speed of 10 m s^(-1) . Calculate the induced emf in the conductor.

The magnetic induction field strength due to a short bar magnet at a distance 0.20 m on the equatorial line is 20 xx 10^(-6) T . The magnetic moment of the bar magnet is