Railway Science (Physics-Electric Current and its Effects) (Part-III)

At each turn, the direction of the induced current changes. The direction of relative motion of the coil and the magnetic field changes every half cycle, the direction of the induced current changes once every half rotation. Magnetic field is a region around a magnetic material or a moving electric charge within which the force of magnetism acts.

The item can be used for a different purpose. Recycling - This involves the process of converting an old item into a new item. Composting - Manure can be formed from organic waste such as fruit and vegetable peels. The manure can then be used as fertilizer for plants. A chemical process in which a substance reacts with oxygen to give off heat is called combustion.

The heat produced by an electric current is equal to the product of the resistance of the conductor, the square of the current, and the time for which it flows. Heat produced in a wire is given by H = 𝐼²Rt in 2 Joule (Where I = current, R = resistance, t = time). Application - Electric iron, electric kettle, electric toaster, electric oven, room heaters, geysers.

Force on a current-carrying conductor in a magnetic field is given as : F = BILsinθ, Where F = force , B= magnetic flux, I = current , L = length of wire. Since in the question given that the angle between the direction of current flowing through a conductor and the direction of magnetic field is zero, So, F = BILsin 0°, F = 0 (sin 0° = 0).

The property of the conductor which opposes the flow of electric current. Work - The scalar product of the force applied on the object and the displacement produced is called work done on the object. Unit - Joule. Electric Current - The rate of flow of electric charge through any cross-section of a conductor. Unit - Ampere. Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field. Unit - coulomb.

Factors on which the magnetic field produced by a straight current-carrying conductor depends : Current in the conductor - The magnitude of the magnetic field produced is directly proportional to the current passing through the wire. Distance from the wire - The magnitude of the magnetic field produced is inversely proportional to the distance from the wire.

Fleming's left-hand rule - When a current-carrying conductor is placed in an external magnetic field, the conductor experiences a force perpendicular to both the field and the current flow's direction. It is used for finding the direction of the magnetic force acting in an electric motor. Thumb (direction of the force experienced by the conductor). Forefinger (direction of the magnetic field) and Middle finger (direction of the electric current).

Fleming's left Hand Rule: The forefinger, middle finger and thumb of your left hand should be spread in such a way that these three are mutually perpendicular to each other. If the forefinger indicates the direction of the magnetic field and the middle finger the direction of the current flowing in the conductor, then the thumb will indicate the direction of motion or the force acting on the conductor.

Magnetic Resonance Imaging (MRI) - MRI uses a powerful magnetic field, radiofrequency pulses, and a computer to produce detailed pictures of internal body structures. CT (Computerised Tomography) scan - Uses X-rays and computers to produce a cross-sectional image of the body. Ultrasound scan - An ultrasound scan uses high-frequency sound waves to make an image of a person's internal body structures. Positron emission tomography (PET) scan - It is a type of imaging test. It uses a radioactive substance called a tracer to look for disease in the body. A PET scan shows how organs and tissues are working.

Electromagnetic Induction is a current produced because of voltage production (electromotive force) due to a changing magnetic field. Discovered - Michael Faraday (1831). Formula, e = N × 𝑑Ф/𝑑t where, e - induced voltage (in volts), N - number of turns in the coil, Φ - magnetic flux, t - time.