Important Science Fact For Railway Exam

1-Tritium is radioactive isotopes of Hydrogen.

2-Tuning of radio is an example of resonance.

3-Cobalt-60 is used in Leukemia treatment

4-Cybernetics is study of communication between human and machine.

5-The filament of Halogen lamp is made of tungsten-iodine mixture.

6-Ceramic is used in Super-conductivity.

7-A transformer which increases the applied e.m.f. of an alternating cur­rent is called Step-up transformer.

8-Transformer, which decreases applied e.m.f. of alternating current is called step-down transformer.

9-A device which convert mechanical energy into electric energy is called dynamo. However, if it produces a fairly large amount of power, it is called Generator.

10-Generator is based on the principle of electromagnetic induction.
in generator, armature consists of laminated soft iron core, from the centre of which passes a steel axle.

11-Slip sings of generator are made of gun metal.

12-Brushes of generator are made out of carbon or gun metal.

13-Coulumb is the unit of electric charge (coulumb = ampere/second).

14-1 coulumb = 6.25

15-Magnetic effect of electric current was discovered by Weston.

16-Ammeter is used in DC as well as in AC.

17-Resistance of Ammeter is very low.

18-Resistance of Voltmeter is very high.

19-Volmeter measures potential difference between two points.

20-A parallel combination of a galvanometer and a small resistance is equivalent to an ammeter.

21-A series combination of a galvanometer and a high resistance is equivalent to a voltmeter.

22-Ammeter is always connected in series while voltmeter is always con­nected in parallel.

23-Electron volt is the unit of energy.

24-Watt is the unit of electric power, watt = volt x ampere =Kilowatt hour (KWH) is also the unit of electric power 1 KWH = 3.6 x J

25-The resistance of low power (watt) bulb is high