Physics (Part-x) (Railway)

The relation between volt-age, current and power is expressed as P = V x I, where P is power, V is voltage, and I is current.

• So, according to the question, P=220 x 2 = 440 watt

A ray of light passing through the centre of curvature of a spherical mirror retraces its path (gets reflected along the same path).

• As the ray of light passes through the centre of curvature of a mirror it strikes the mirror along the normal i.e.. it incidences on to the mirror at 90 degrees.

• When the object is placed the at the center of curvature, then a ray parallel to the principal axis and another ray that passes through the principal focus (f) after reflection, intersect each other at point right below where the object s positioned.

• Hence the properties of the images formed in this case are that image is formed at the center of curvature, the image is the same size as the object and images are real and inverted.

An incident ray which passes through the center of curvature C of the mirror is reflected back along its own path.

• Hence the incident ray coincides with the normal.

• Therefore, angle of incidence is 0 degree.

The rating for a fuse used in a household electric circuit is provided on the basis of the current.

• For domestic purposes, fuse is rated in the range of 1 Ampere to 10 Ampere.

• The fuse is used to provide over current protection.

• The Fuse is made up an alloy of tin (Sn) and lead (Pb).

Fleming's right hand rule is used to find the direction of the induced current.

• According to Fleming's right hand rule, if we stretch the thumb, middle forger and fore finger of our right hand mutually perpendicular to each other such that the forefinger, Indicates the direction of magnetic field and thumb indicates the direction of motion of conductor, then the middle finger will indicate the direction of induced current.

When current flows through a conductor, heat energy is generated in the conductor. It is treated as loss.

• Heat is generated in a circuit because when electron flow is resisted, some of the energy in the electrons does not travel through all the way.

• Because energy is conserved. the energy that was moving the electrons forward is converted to heat energy.

Electromagnetic induction is the process of generating electric current with a magnetic field.

• It occurs whenever a magnetic field and an electric conductor, such as a coil of wire, move relative to one another.

• As long as the conductor is part of a closed circuit, current will flow through it whenever it crosses lines of force in the magnetic field.

Aperture is the effective diameter of the circular outline of a spherical lens through which refraction takes place.

Electrolysis is the process of using electricity to split water into hydrogen and oxygen.

• Hydrogen gas released in this way can be used as hydrogen fuel, or remixed with the oxygen to create oxyhydrogen gas

The relationship between magnification and focal length of a spherical mirror is given by m = f/(f -u), where m is magnification, f is focal length and u is the object distance

• So according to the question, m=2.5/2.5-5=2.5/-2.5=1