Unit 2 Post Test: Optics

The frequency of which type of electromagnetic wave is just higher than that of visible light?

• ultraviolet rays

• gamma rays

The wavelengths for visible light rays correspond to which of these options?

• about the size of a virus or a large molecule

• about the size of a football field

Which sequence shows the different types of electromagnetic waves arranged in an increasing order of their frequency?

• visible light, x-rays, radio waves, microwaves

• radio waves, microwaves, visible light, x-rays

Which type of electromagnetic wave is invisible, but close to visible light, with wavelengths about the size of a virus or a large molecule (1 raise x 10^-8 to 4 x 10^-7 meters)?

• microwaves

• ultraviolet rays

Which property of light remains unchanged when it enters a different medium?

• frequency

• wavelength

If light travels from oil (slower medium) to water (faster medium) at an angle, what happens to the direction of the light ray in water with respect to normal?

• It moves toward the normal.

• It will move perpendicular to the normal.

Why do underwater objects appear distorted when you see them from above?

• diffusion

• refraction

Light incident on a surface at an angle of 45° undergoes diffused reflection. At what angle will it reflect?

• at any angle between -90° and 90°

• only at angles less than 45°

What is true about the refractive index of a medium?

• It increases with a decrease in angle of refraction.

• It is independent of any change in angle of incidence or angle of refraction.

When an object is at a distance of twice the focal length from a concave lens, the image produced is virtual and smaller than the object. What happens to the image if the object is shifted closer to the lens to a point one focal length away from it?

• The image produced is virtual and of the same size as the object.

• The image produced is virtual and enlarged.