Question

1) if the angle of incidence is greater than the angle of refraction for a light ray, is the speed of light faster in a second material? explain your answer

2) a student needs a 100 ohms resistor for a circuit , but he only has a box of 300 ohms resistor, can the 300 ohms resistor be combined to make a 100 ohms resistor?

3) Explain how can you determine the types of radiation emitted by a nucleus when it radioactively decays?

Answer 1

1) During refraction, although the speed changes and wavelength changes, the frequency of the light will be constant. The frequency, wavelength, and speed are related by:

The change in speed that occurs when light passes from one medium to another is responsible for the bending of light or is what we call as refraction, that takes place at an interface. If the light is traveling from medium 1 into medium 2, having refractive indices n1 and n2 respectively and angles are measured from the normal to the interface, the angle of transmission of the light into the second medium is related to the angle of incidence by Snell's law :

if the angle of incidence is greater than the angle of refraction for a light ray, then,

So the speed of light is faster in the first medium

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2. Given he has resistors of . In order to have the effect of , he has to take only three resistors,

In order to obtain the effect of , he must connect all the resistors in parallel.

Effective resistance in a parallel circuit is given by,

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3. To determine the type of radiation emitted, first, determine the background count rate, then the source count rate with no absorber.

Now place a sheet of paper between the source and the monitor. If the counts are significantly reduced, then the particles emitted by the source are alpha particles.

If the count rate is not significantly reduced, place a 2 mm thick sheet of aluminum between the source and the monitor. If the count rate goes almost to the background level, then the particles emitted by the source are beta particles.

If the count rate is only reduced, then the radiation emitted by the source are gamma radiations.