You want to design a toy puppy that will bark whenever anyone walks past its sensor. which type of electromagnetic radiation would your design use?

a. ultraviolet radiation
b. visible light
c. gamma rays
d. microwaves

When anyone pass the puppy then it will block the visible light that incident upon it

So here we are blocking the visible part of light by passing the puppy which means we have to design a sensor that will sense the visible light.

So here the electromagnetic part of the sensor is capable to detect this change only

so here correct answer must be

B. Visible Light

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