## How do you calculate induced current in a solenoid?

An emf voltage is created by a changing magnetic flux over time. If we know how the magnetic field varies with time over a constant area, we can take its time derivative to calculate the induced emf. The current through the windings of a solenoid with n=2000 turns per meter is changing at a rate dI/dt=3.0A/s.

**What type of current is induced in solenoid?**

The magnet will induce a current in any loop through which it passes. If the solenoid is a single piece of conductive material, a current induced in one loop will produce current throughout the whole thing. This current is due to changing magnetic flux in the loop.

### How do you increase the induced current in the solenoid?

The strength of the magnetic field around a solenoid can be increased by:

- increasing the number of turns on the coil.
- increasing the current.
- placing an iron core inside the solenoid.

**How do you calculate the emf of a solenoid?**

Calculating the induced EMF Faraday’s law states: Induced EMF is equal to the rate of change of magnetic flux. Magnetic flux = Magnetic field strength x Area = BA. Therefore…Induced EMF = (change in Magnetic Flux Density x Area)/change in Time. Therefore, Induced EMF = (Bπr2n)/t.

#### How do you create an induced current?

This change may be produced in several ways; you can change the strength of the magnetic field, move the conductor in and out of the field, alter the distance between a magnet and the conductor, or change the area of a loop located in a stable magnetic field.

**What is needed to induce current in a solenoid?**

Moving the bar magnet into the solenoid induces an e.m.f. in the solenoid (according to Faraday’s law), and because the circuit is closed, a current flows and a magnetic field is induced.

## Why does current flow in a solenoid?

A solenoid is a coil of wire with electric current flowing through it, giving it north and south magnetic poles and a magnetic field. Using more turns of wire in the coil or more current increases the strength of the solenoid’s magnetic field.

**At what rate is the current in the solenoid changing?**

The rate of change of current in the solenoid is 5.15A/s.

### Can a coil outside a solenoid be induced?

Usually it’s assumed that the current is small enough so the second term can be ignored. And even that statement is approximate. The complete solution must include the ring-induced flux modifying the solenoid flux, since ring flux couples into the solenoid just as solenoid flux couples into the ring. But we won’t go there this time.

**How is the direction of induced current in a solenoid determined?**

We would use a setup as in this sketch to do the test: In the case where a north pole is brought towards the solenoid the current will flow so that a north pole is established at the end of the solenoid closest to the approaching magnet to repel it (verify using the Right Hand Rule):

#### Will EMF induce in current carrying conductor in solenoid?

If a current carrying conductor is placed inside a solenoid where current passes through both solenoid & conductor, Will an extra emf (potential difference)/current induce in the conductor? [current in conductor is less than that of solenoid]? Let emf already existing in conductor be E1.

**How to find the direction of the induced current?**

The induced magnetic field is in a direction that tends to cancel out the change in the magnetic field in the loop of wire. So, you can use the Right Hand Rule to find the direction of the induced current by remembering that the induced magnetic field is opposite in direction to the change in the magnetic field.