Electromagnetic Waves and Polarisation Worksheet

According to the diagram, what do the E and B arrows represent in an electromagnetic wave?

• Electric and sound fields

• Electric and magnetic fields

• Magnetic and gravitational fields

• Sound and gravitational fields

Why did Isaac Newton compare polarised light to iron filings around a magnet?

• Because light was attracted to metal

• Because light particles aligned in a specific direction

• Because light was refracted by magnets

• Because light was absorbed by iron

Which of the following best describes what happens when unpolarised light passes through a polarising filter?

• All light is absorbed by the filter

• Only light waves in the plane of the polariser pass through

• The light becomes more intense

• The light changes color

What happens if the plane of the analyser and the polariser are at right angles to each other?

• Maximum light is transmitted

• No light is transmitted

• The light becomes unpolarised

• The light changes direction

Which of the following is a use of Polaroid sunglasses?

• They increase the brightness of light entering the eyes.

• They block annoying reflections from horizontal surfaces.

• They amplify sound waves.

• They are used to store electrical energy.

A student is looking at reflected light off a pond with polarising glasses and slowly turns the glasses through 180°. What would they most likely observe?

• The brightness of the reflection remains constant.

• The reflection disappears and reappears as the glasses are rotated.

• The color of the pond changes.

• The temperature of the glasses increases.

Explain why we are more interested in the intensity of light received rather than the total energy emitted by a source.

• Intensity tells us the color of the light.

• Intensity determines how much energy is received per unit area, which is more relevant for practical applications.

• The total energy emitted is always the same for all sources.

• Intensity is easier to measure than total energy.

If the intensity of radiation from the Sun at the distance of Earth (1 AU) is 1367 W m⁻², what would be the approximate intensity at the distance of Mercury (0.387 AU), assuming no absorption or scattering?

• 9126 W m⁻²

• 456 W m⁻²

• 1367 W m⁻²

• 3870 W m⁻²

Recall whether intensity follows the inverse-square relationship with distance. Explain what this means.

• Intensity increases with the square of the distance from the source.

• Intensity decreases linearly with distance from the source.

• Intensity remains constant regardless of distance.

• Intensity decreases with the square of the distance from the source.

A bright flashlight has a light intensity of 15.0 W m⁻² at a distance 1.00 m away. Calculate the intensity of the flashlight at 100.0 m distance.

• 0.0015 W m⁻²

• 0.00015 W m⁻²

• 0.15 W m⁻²

• 1.5 W m⁻²