Define the term, ‘Critical Angle’. What is meant by ‘total internal reflection’? State two essential conditions for total internal reflection to take place. With the help of a ray diagram, illustrate an application of total internal reflection. OR (a) What is meant by a ‘magnetic field’? (b) How is the direction of magnetic field at a point determined? (c) Describe an activity to demonstrate the direction of the magnetic field generated around a current carrying conductor. (d) What is the direction of magnetic field at the centre of a current carrying circular loop?

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Answers

2016-02-10T10:39:14+05:30
Critical angle: the angle of incidence in the denserer medium corresponding to which the angle of refraction in the rarer medium is 90 degrees

total internal reflection: When a ray of light travelling in the denser medium is incident on the surface of the rarer medium, such that the angle of incidence is greater than the critical angle for the pair of media, the ray of light is completely reflected in the denser medium, this phenomenon is called TOTAL INTERNAL REFLECTION

conditions for total internal reflection are:
1 the light ray must travel from denser medium to rarer medium
and,2  the angle of incidence must be greater than the critical angle for the pair of media
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