Question

1) Which one of the following is not a property of EM waves in a vacuum?
a) The EM wave is longitudinal, the electric and magnetic fields oscillate along the direction of propagation.

b) The electric and magnetic fields oscillate in phase with each other.  

c) EM waves in a vacuum travel at a speed of 3.00 × 10⁸ m/s, independent of frequency.

2) Which one of the following statements is correct?
a) A complete description of light requires consideration of both particle-like and wave-like behaviour.

b)All of the observed behaviour of light can be explained by modelling light as a wave.   

c) All of the observed behaviour of light can be explained by modelling light as a stream of particles.

3)When a ray of light passes into a medium with a higher index of refraction...
a)the speed of the light decreases and the ray is bent toward the normal.

b)the speed of the light increases and the ray is bent toward the normal.  

c) the speed of the light decreases and the ray is bent away from the normal.

Answer 1

Ans

1) Option a is not the property of the EM wave. The EM wave is a transverse wave and both fields oscillate perpendicular to the direction of propagation of the wave.

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2) Option a is correct. A complete description of light requires consideration of both particle-like and wave-like behaviour. Light can exhibit particle-nature or wave-nature depending on the situation

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3) The speed of light in a medium is given by

v = c / n where c = speed of light and n = refractive index

so clearly when a ray of light passes into a medium of higher index of refraction the speed of light decreases. Using Snell's law(or Fermat's least time principle)) the ray is bent towards the normal.

Hence option a is correct.